Chairs: Alfonso Farina, Leonardo SpA; Michael Brandfass, Hensoldt Sensors GmbH
8:00 AM – 19: HE-R1000 Antenna Feed System developed by Thale Alenia Space in Italy
Giuseppe Orlando (Thales Alenia Space)*; Giovanni Gasparro (Thales Alenia Space); Gianpiero Fabiani (Thales Alenia Space); Danilo Fortini (Thales Alenia Space); Raffaele Carnesecchi (Thales Alenia Space); Giulio Adone (Thales Alenia Space); Davide Landi (Thales Alenia Space)
The paper provides an overview of the dual reflector afocal imaging system fed by an active phased array for Earth Observation developed by ThalesAleniaSpace in Italy (TAS-I). In section II, an overview on X band active antennas heritage is presented with a focus on Cosmo SkyMed and Cosmo Second Generation products while in section III, HE-R1000 antenna is described, going into details of Large Unfurable Reflector Assembly (LURA), Feed Array Assembly (FAA) and their integration into SAR Antenna Subsystem (SAS).
8:20 AM – 22: A Technique for on-site Calibration of Active Phased Arrays Using Two Probes
Matteo Ciattaglia (LEONARDO)*
The first calibration of active phased arrays is usually performed in factory using Near Field facilities. In most cases, the calibration can be repeated on site using built in calibration networks, reference measurements performed during the factory tests or expensive equipment. This paper explores a calibration technique that does not need factory reference measurements and that is based on on-site measurements from two external probes.
8:40 AM – 36: Recent Advances on Wideband Wide Scanning Connected Slot Arrays
Daniele Cavallo (Delft University of Technology)*
Connected slot arrays with artificial dielectric layers (ADLs) are a type of wideband wide-scanning arrays with several favorable properties. A key advantage is the high front-to-back ratio provided by the artificial dielectric, which allows to keep the distance between the radiating slots and the ground plane lower than a tenth of the wavelength over the entire frequency band of operation. This results in low-profile array designs the can be realized with multi-layer planar printed circuit boards at microwaves and millimeter waves. Another important feature is the anisotropy of the ADLs, which yields wide scanning capability without supporting the propagation of surface waves. An overview of different array designs based on this concept is given here, together with a description of the typical design steps and the achievable performance.
9:00 AM – 37: Digitally Synthesized Antenna Test Bench for Next Generation Phased Array Systems
Antonio Ciociola (Leonardo S.p.A.)*
With the increasing digitalization of radar new test benches must be employed for antenna measurements. The conventional antenna testing approach cannot be applied to fully digital phased array antenna systems. This paper explores the new challenges regarding the testing of a digital array radar which cannot be performed using a conventional network analyzer. In this case the measurement must be performed using a couple of generator/I-Q analyzer that have to be locked to the system under test during the measurement in order to ensure phase coherence of the transmitting and receiving pulse. This paper addresses a strategy to generate an auxiliary reference in the RF domain to compensate for the phase variation over the measurement time.
9:20 AM – 108: Technology developments and R&D activities at the European Space Agency for satellite communication payloads based on active antennas and digital processors
Salvatore D’Addio (European Space Agency)*
This paper provides an overview of some of the recent technology developments and R&D activities supported by the European Space Agency for next generation satellite communication payloads based on active antennas and on-board digital processing functions. In particular, recent technology developments on active antennas for LEO, MEO and GEO missions, including HPA MMICs, are presented. An introduction to R&D activities in the area of digital signal processing and digital beamforming, as well as in signal processing techniques for MIMO satellite systems is also provided. Possible future satellite systems supporting 5G are also introduced.
9:40 AM – 158: Development of Antenna Array Technologies at ONERA
Hervé Jeuland (ONERA)*; Cedric Martel (ONERA); Sylvan Bolioli (ONERA); Aurelie Dorle (ONERA); André Barka (ONERA)
This paper presents the recent activities carried out at ONERA in the field of antenna arrays using PCB technologies. These activities cover principally wideband applications with strong integration constraints, which require very low profile antennas. Two examples of antenna array developed at ONERA are presented in the paper.
10:00AM – BREAK
10:30 AM – 42: Analysis and Experimental Validation of Direction-Finding Systems for ELINT Applications
Daniele Marcantoni (Elettronica SpA)*; Riccardo Ardoino (Elettronica SpA); Goffredo Foglia (Elettronica SpA)
The Direction Finding (DF) problem is well known in the Electronic Support Measures (ESM) and Electronic signal Intelligence (ELINT) applications domain. The capability to achieve a high accuracy estimation of the angle of arrival (AOA) can be obtained by using interferometric techniques at the expense of phase ambiguity and phase errors due to the receiver unbalances. The paper presents the design implementation and experimental results of interferometric systems with a focus on wide band applications.
10:50 AM – 50: Investigation and Mitigation of Scan Blindness for State-of-the-Art Broadband Apertures
Marc Vizcarro i Carretero (Hensoldt Sensors GmbH)*; Mario Leib (Hensoldt Sensors GmbH); Tobias Trombatore (Hensoldt Sensors GmbH); Michael Sabielny (Hensoldt Sensors GmbH)
This paper describes a scan blindness investigation and mitigation study through review and design of broadband (>4:1, RL >10 dB), wide-scan (±60°), dual-polarized (linear HV) and low-loss (<0.5 dB, >90%) active electronically scanned array (AESA) apertures suitable for military airborne applications. Two state-of-the-art broadband radiator candidates are assessed and compared: the Planar Ultrawideband Modular Antenna (PUMA) and a combined Bunny Ear / Banyan Tree Antenna (BE/BT-A). Given the constrained non-grating lobe free spacing (d > λhigh/2), scan blindness arising from parasitic current paths and cavities between array elements are shown to be critical both in terms of active impedance match and polarization purity. Upon scan blindness investigation and successful mitigation, the BE/BT-A proves to be a robust candidate against a non-optimally sampled grid. Thus, enabling low-loss and highly compact TRM/aperture integration concepts to be included in future Multi-Function RF Sensor (MFRFS) systems.
11:10 AM – 53: Design and Realization of a Highly Integrated and Scalable X-Band Tile Array
Ralf Rieger (Hensoldt Sensors GmbH)*; Thomas Mueller (Hensoldt Sensors GmbH); Alexander Mueller (Hensoldt Sensors GmbH); Markus Boeck (Hensoldt)
“Modern active antennas are often assembled with hundreds or even thousands of transmit/receive modules. Thus, large numbers of these modules along with their mechanical infrastructure form a dominating factor with regard to size, weight and especially cost of such active antennas. Concerning all these parameters a quantum leap is achieved by the evolution from brick modules used to build up plank based active antennas to tile-based arrays. Key enabler for this step is the huge progress made in the field of semiconductor technologies, especially Gallium-Nitride (GaN) and Silicon-Germanium (SiGe). The integration of all the Tx/Rx module’s RF functionalities into two multifunctional MMICs made it possible to accommodate them within the typically available area of half the wavelength squared. This paper describes the development activities towards an X-band tile array performed at HENSOLDT during the last years. This includes not only the in-house design of a suitable GaN-frontend chip and a customized SiGe-beamformer chip, but also the generation of a radiating element and an RF manifold, both integrated within the tile’s PCB.”
11:30 AM – 98: On The Relationship Between Array Lattice and the Active Element Pattern of Antenna Arrays
Giovanni Petraglia (MBDA)*; Pietro vinetti (mbda); Fabio Pascariello (mbda)
The active element pattern is very often omitted or assumed isotropic when dealing with antenna array design. This assumption inevitably leads to a paradox. This paper tries to solve the paradox showing that a strict relationship exists between the array lattice of the array and the active element pattern of the array element. Starting from application of the Power Conservation Law, it is shown that the active element pattern must change with the lattice and assuming the constant/isotropic behavior leads to unfeasible and un-realistic approximation. The relationship is demonstrated by using a full wave model of a representative array.
Chairs: Alfonso Farina, Leonardo SpA; Michael Brandfass, Hensoldt Sensors GmbH
1:30 PM – 91: CROWN Project, towards a European Multifunction AESA System
María Luz ML Gil (Indra Sistemas)*; Michael Brandfass (Hensoldt); Sebastian Durst (Fraunhofer); Isabelle LeroyNaneix (Thales); Philippe Brouard (ONERA); Antonio Nanni (Leonardo); Ubaldo Calfa (Elettronica); Mattias Thorsell (Saab); Tomas Boman (FOI); Jacco de Wit (TNO); Mantas Sakalas (Baltic Institute of Advanced Technology); Alvaro Cubillo (Indra Sistemas); José Luis Galan de la Haba (Indra Sistemas); José Correcher Soriano (Indra Sistemas)
The project European active electronically scanned array with Combined Radar, Electronic Warfare (EW) and Communications (COMMs) functions for military applications, called CROWN, was launched in July 2021 under the European program of Preparatory Action for Defence Research (PADR) and Electromagnetic Spectrum Dominance Call. It responds to the need of designing and developing high-performance and very compact Multifunction RF systems. Multifunction systems, integrating several functions in only one single system, enable small platforms operating in the complex battlefield of high capabilities, able to adapt and react in real-time to the changing scenarios and working in collaborative way with other systems. Technological challenges are found in the development of broadband antennas, digital beam forming (DBF), smart resource management and compact transmit and receive modules. Other aspects at system level as architecture definition or modelling are also tackled within the project.
1:50 PM – 104: GESTRA – upgrading to future distributed phased array radar networks for space surveillance
Christoph Reising (Fraunhofer FHR)*; Markus Gilles (Fraunhofer FHR); Rudolf Hoffmann (Fraunhofer FHR); Steven Horstmann (Fraunhofer FHR); Stephan Schneider (FraunhoferFHR)
“More and more objects are orbiting the Earth. Especially mega-constellations lead to a big number of artificial objects in space, both active and debris. This increasing amount of space debris is becoming more and more dangerous for human spaceflight. An accurate catalogue of the debris particles orbiting the Earth enables satellites to avoid collisions. The space surveillance radar GESTRA, which was developed by Fraunhofer
FHR, is a first step to create a German catalogue of objects in space. Additional transmitter and receiver units are built to create a distributed phased array radar network to increase the detection performance and accuracy of the GESTRA systems, allowing to detect even smaller debris particles with simultaniously decreased estimation uncertainity”
2:10 PM – 75: Design of TR Module Components for Ultra-Wideband Arrays up to Ka Band and Beyond
Mantas Sakalas (Baltic Institute of Advanced Technology)*; Paulius Sakalas (Baltic Institute of Advanced Technology)
“This work presents design of key Transmit/Receive (TR) module components for ultra-wideband phased arrays. A Low Noise Amplifier (LNA), a Down-Conversion Mixer (Mixer) and an Active Balun (Balun) were designed in 0.1 μm GaAs technology for the Receive (RX) module. The Transmit (TX) module was addressed with a Power Amplifier (PA) design in 0.15 μm GaN on SiC. The circuits were optimized with emphasis to achieve the maximum degree of integration, minimum Direct Current (DC) power consumption and ultra-wide bandwidth. Furthermore, a dedicated model for each of the (RX) components was created based on the measurement results. The models were then added together to form a Computer Aided Design model of the (RX) module. By this means the performance of the RX module was simulated. Promising results were achieved with respect to the targeted design goals, demonstrating the potential for integration of the designed components into a (TR) modules for future ultra-wideband arrays.”
2:30 PM – 73: Customizable Phased Array Antenna based on Domino Tiles for Satcom Applications
Federico Boulos (German Aerospace Center (DLR))*; Ulf Johannsen (Eindhoven University of Technology (TU/e)); Stefano Caizzone (DLR)
In recent years, phased array antennas are emerging as a key solution for satellite communications (satcom) ground terminal to provide global connectivity everywhere by satellite. To satisfy the user throughput requirements, the ground terminal has to transmit/receive the satellite signal with an high directive and steerable beam able to track satellites also close to horizon. In order to do that, phased arrays with a huge amount of elements are needed, posing a challenge in terms of design, manufacturing and costs. The following paper proposes ways to cope with manufacturing and design issues of large aperture by introducing modularity into the system. A domino subarray for Ka frequency band is presented and arranged to build customizable aperture.
2:50 PM – 39: Virtual Distancing: A Beam-Steering Technique for Interference Reduction in Multibeam Antennas
Piero Angeletti (European Space Agency)*; Riccardo De Gaudenzi (European Space Agency)
“The interference reduction techniques described in the paper are based on the observation that in multibeam antennas, the beam positions determine the useful gains and unwanted interference for all co-channel users. An optimization of the beam positions which guarantees a useful gain for the wanted user while reducing the interference to the co-channel users can obtain interference reduction and overall throughput improvement. Inspired by the recent emphasis on “social distancing” to prevent virus transmission, we termed these techniques “virtual distancing”. A continuous and a quantized version of the technique are described together with implementation aspects. A simplified approach to the continuous optimization problem exploits analogies with molecular dynamics. Performance results are reported for a geostationary multi-beam satellite Ka-band study case.”
3:10 PM – 40: SWAN(TM) – CAD Tool for the Design and Analysis of Large Beam Steering Slotted Waveguide Arrays
Roberto Vincenti Gatti (University of Perugia)*
Flat profile and high performances in terms of efficiency and power handling make slotted waveguide arrays attractive for many applications, ranging from radar systems to satellite and terrestrial communication systems. Apertures with hundreds or thousands of radiating slots are needed to satisfy typical requirements on beamwidth and gain. The design and analysis of such large slotted waveguide arrays is therefore extremely burdensome, if carried out with commercial 3D full-wave software tools, because of the considerable computational effort required. SWAN(TM), a powerful CAD tool for the design and analysis of this kind of antennas, is presented in this paper. High computational efficiency, accuracy and reliability of the software are demonstrated by specific examples and by comparison between simulations and measurements.
3:30 – BREAK
4:00 PM – 41: Beam steering of vortex waves by a phased array based on the field equivalence principle
Altunkan Hizal (Aselsan Inc)*
A further ability can be added to an existing phased array (PA) to include generation and steering of noncollimated or collimated electromagnetic vortex waves (VW). The concept is based on the field equivalence principle. The near field of VW’s generated by a uniform circular array (UCA) is calculated on a tilted planar finite size reference aperture (RAP) which intercepts all the VW modes. Using the Love’s equivalence principle and the vectorial VW fields on the RAP, the VW’s are calculated in the far field. RAP is divided into small rectangular subapertures (SAP), simulating the elements of a PA. On each SAP, the VW’s fields for given RAP’s tilt angle (steering angle) are calculated. These fields are to be generated by appropriately polarized PA’s antenna elements fed by the associated transmit-receive modules. The method is also applied to VW’s tightly collimated by a paraboloidal reflector. Numerical simulations obtained verified this concept.
4:20 PM – 161: A Dual-Polarized Low-Profile Wideband Antenna Array with Wide-Scan Ability
Tutku Bakan (ASELSAN)*; Burak Alptuğ Yılmaz (ASELSAN); Çağrı Çetintepe (ASELSAN); Lale Alatan (METU)
“This paper presents a novel hybrid-fed, low profile, dual polarized antenna element for phased array applications. Proposed antenna element supports a wide scan range of ±45°, ±60° and ±75° on its E-, H- and D-planes, respectively, over a wide frequency band of 8.8-11.5 GHz with an active VSWR below 2.5:1 4for each polarization channel. The antenna features a low complexity, comprising four RO3003 layers and a set of vias which serves to mitigate higher order mode propagation for the feeds. Utilized hybrid feeding method helps to increase the isolation
between the ports, which is higher than 13 dB at broadside. Dual feed lines of the first port and an internal matching network at the
second port improve the impedance bandwidth at 50 Ω coaxial connector interfaces of the antenna. Low profile of the developed
antenna element enables conformal phased array applications.”
4:40 PM – 173: Quasi 5 foci Rotman-Turner Discrete Lens Antennas with Minimised Optical Aberrations
Giovanni Toso (European Space Agency)*
Discrete Lens Antennas guarantee several advantages including a true time delay behavior, simplified beamforming networks, large field of view, high number of radiated beams. Despite to several papers proposed on the design and applications of two-dimensional constrained lens antennas, and in particular on the Rotman–Turner lens, a rigorous study focused on the minimization of optical aberrations does not seem to be available. The main results of a general procedure for the design of two-dimensional bootlace lens antennas with a flat front profile are proposed in this paper. It will be shown that the best performance is achievable when, in addition to the three nominal focal points, two additional symmetric quasi foci are present. It will be shown also that a completely different two-dimensional discrete lens, characterized again by a flat profile and 4 focal points, presents minimized aberrations when the presence of one additional quasi focus on the lens axis is guaranteed. Interestingly, both the 3- and 4-foci lenses, when optimized, converge to the same configuration which exhibits aberrations following a Chebyshev-like behavior and guarantees quasi 5 foci.
Chairs: Tim Hancock, Raytheon Technologies; James Wilson, DARPA
8:00 AM – 5: UWB Hemispherical Vivaldi and BAVA Arrays for Wide Angle Scanning
Carl Pfeiffer (Air Force Research Laboratory)*; Jeffrey Massman (Air Force Research Laboratory)
We report the first ultra-wide band (UWB) arrays on a doubly curved surface for wide angle electronic scanning. Two different prototypes are developed employing Vivaldi antennas and balanced antipodal Vivaldi antennas (BAVAs) distributed over the surface of a hemisphere. The arrays employ 52 dual-polarized elements. Unit cell simulations demonstrate a good impedance match from 2-12 GHz, and finite array simulation have a realized gain that is within 1 dB of theory. The antennas and are metal 3D printed from titanium. Measurements of the arrays will be reported at the conference.
8:20 AM – 147: Low-Power K/Q-Band Digital Phased Array Chiplet
Craig A Hornbuckle (Jariet Technologies, Inc.)*; Eric Mrozek (Jariet Technologies, Inc.); Marcel Lugthart (Jariet Technologies, Inc.); Thomas Krawczyk (Jariet Technologies, Inc.)
The DARPA Millimeter Wave Digital Arrays (MIDAS) program has developed an extremely low-power integrated circuit (IC) operating from 18 to 50 GHz for use in a tiled Active Electronically Scanned Array (AESA) implementation. Each chiplet provides thirty-two transmit and thirty-two receive channels with partial beamforming in the digital domain, supporting dual-polarized operation over sixteen antenna elements with very high dynamic range. This chiplet is designed such that multiple copies of the higher-level tile assembly may be formed into arrays of an arbitrary size through abutment. This paper will describe the architecture, implementation, and performance for this ground-breaking CMOS monolithic device. Descriptions of the key circuit blocks are included as well as the simulated performance of key sub-circuits.
8:40 AM – 157: MIDAS mmW Aperture
James McSpadden (Raytheon Technologies)*; Jason Milne (Raytheon Technologies)
Raytheon Technologies teamed with Michigan State and Teledyne Scientific present a 16-element scalable AESA building block consisting of high efficiency InP HBT power amplifiers (PAs), low noise figure InGaAs HEMT Low Noise Amplifiers (LNA) with integrated T/R switches, a high-density tile interposer containing the TA1 Digital Tile, and wideband antenna to meet the MIDAS TA2 program goals. The architectural, device, and assembly technology choices are presented with Phase 1 results.
9:00 AM – 156: MIDAS Wideband mmW Digital Tile
James McSpadden (Raytheon Technologies)*; Lawrence Kushner (Raytheon Technologies)
Raytheon Technologies teamed with Michigan State University and Teledyne Scientific present a zero-IF, mixed-signal, 32-channel millimeter-wave CMOS transceiver design developed under the DARPA/MTO MIDAS program. The architectural choices, design overview, and measured results from two generations of ASIC development are presented. As part of the MIDAS 3D T/R module, element-level digital beamforming provided by this ASIC will allow multiple simultaneous beams over a wide field of regard.
9:20 AM – 142: An 18-50 GHz RF-CMOS Transmitter Front-End for a Digital Phased Array System
Shih-Chang Hung (Michigan State University)*; Asad Ali Nawaz (Michigan State University); Matt Hodek (Michigan State University); John Albrecht (Michigan State University); Sang-Min Yoo (Michigan State University)
An ultra-wideband 18–50 GHz millimeter-wave (mm-wave) transmitter is presented. The proposed mm-wave transmitter is designed for compact size and low-power consumption, and it is suitable for an element-level digital phased array system. The fully-integrated transmitter includes buffers, cascaded baseband amplifiers with sharp roll-off, a local oscillator (LO) driver, a broadband coupled line coupler, and a stacked active mixer fabricated in a 45-nm SOI CMOS process. The cascaded Sallen-Key filters are implemented to provide sharp roll-off to remove the aliasing tones from the DACs and have moderate gain to reduce the gain required of the following mixer and PA stages. The LO driver is paired with a differential broadside coupler to generate the differential in-phase (I) and quadrature (Q) LO signals locally to ensure abrupt switching of the mixer. The phase imbalance of the I and Q LO signals can be tuned out by the tunable resistance at the isolation port of the broadside coupler. The stacked double-balanced active mixer mitigates the requirement for bulky inductors between transmitter building blocks. This allows the whole transmitter to be implemented within a limited area much smaller than the array spacing to allow area for other chip functions. The resulting transmitter has a compact chip area of 0.550.85 mm2 including pads. The prototype demonstrates a maximum 14.8-dB power gain and excellent gain flatness across the frequency range of interest.
9:40 AM – 155: Millimeter Wave Digital Arrays (MIDAS) TA2: Millimeter-Wave Scalable Unconstrained Broadband Arrays (MMW SCUBA)
Josephine Chang (Northrop Grumman Mission Systems)*; Ryan Walsh (Northrop Grumman Mission Systems); Fadi Afiouni (Northrop Grumman Mission Systems); Sean McLoughlin (Northrop Grumman Mission Systems)
The Millimeter-Wave Scalable Unconstrained Broadband Array (MMW SCUBA) system leverages cutting edge chip integration, additive manufacturing, and packaging technology to realize an 18-50 GHz, dual-polarized, scalable phased array antenna with element-level digital beamforming. We report on the demonstration and test of a 16 element free-space-to-RF prototype, as well as progress on the development of a larger 64 element array prototype build which extends integration from free-space to digits.
10:00 AM – BREAK
10:30 AM – 57: A New Phased Array Construct: Intra-element Monoliths Printed & Attached to a CircuiT board (IMPACT)
Victor C Sanchez (Jacobs Technology Inc)*
A new realization of broadband phased array is introduced. The structure consists of individual additively manufactured metallic radiating elements excited through coaxial apertures on a conventional printed circuit feed board. Metallic intra-element structures which we refer to as “monoliths”, include well-known broadband features such as a Vivaldi-like flare, tight capacitive coupling to neighboring elements, and built-in shorting posts to provide a balanced feed. The construct includes additional performance-enhancing RF features such as height-variable capacitance as well as RF-benign mechanical features which make the construct light weight, repeatable, and suitable for automated pick-and-place fabrication.
10:50 AM – 71: Demonstration of X-Band Wideband Scanning Using Hybrid Beam Steering Components
Virendra Kumar (Defence Research and Development Organisation(DRDO))*; Shreeshail . (Defence Research and Development Organisation(DRDO)); Srinivas D (Defence Research and Development Organisation(DRDO)); Pramod Kumar (Defence Research and Development Organisation(DRDO)); K SREENIVASULU (DRDO); Beenamole KS (Defence Research and Development Organisation(DRDO)); Ravi Gangwar (IIT(ISM) Dhanbad)
This paper demonstrates the use of hybrid beam steering components for wideband electronic scanning. A uni- directional multifunction monolithic microwave integrated circuit (MMIC) core chip is combined with three numbers of single pole double throw (SPDT) switches to realize bi-directional TTD units for transmit and receive operation. The realized bi-directional TTD unit is characterized by its functionality at the four-element subarray for true-time delay beam steering. The 6-bit digitally controlled phase shifters and a 6-bit true-time delay (TTD) units are used in a hybrid configuration to realize an X- band wideband 16-element linear array. The element level phase delay (limited to a maximum 360 deg) and subarray level time delay in steps of 3.125 ps (maximum delay of 197ps) is applied for the array calibration and beam steering. The radiation pattern is measured at the center operating frequency f0, and the beam is steered at f0 + 0.5 GHz to validate squint-free beam scanning. The proposed configuration with a two-stage hybrid phase/time delay demonstrates the wideband beam steering and eliminates the beam squint for wide instantaneous signal bandwidth for high- resolution imaging active phased array radars.
11:10 AM – 77: Development of Balanced TCDA for MFAs
Alexander D Johnson (BAE Systems)*; Jacob Tamasy (BAE Systems); James Fung (BAE Systems Inc); Benjamin Mcmahon (BAE Systems Inc)
Multifunctional arrays (MFAs) are widely used in RF sensing, radar, and communications applications. Advancements in packaging technologies, high data rate converters, and ultra-wideband (UWB) RF electronics have enabled the proliferation of such systems. Another key enabler of the MFA is the advent of powerful electromagnetic software that allows for the design of novel UWB array apertures. In this paper, we present a new addition to the tightly coupled dipole array (TCDA) family of UWB array apertures. The presented balanced TCDA retains higher bandwidth, lower costs, better polarization purity, and lower volumes than current aperture solutions.
11:30 AM – 118: An Ultra-Wideband Fully-Planar Inverted-L Monopole (FILM) Array
Muhammad Hamza (Florida International University)*; Constantinos L. Zekios (Florida International University); Stavros Georgakopoulos (Florida International University)
A new ultra-wideband array is introduced, called the fully-planar inverted-L monopole (FILM) array. The proposed array is the first ever reported tightly coupled monopole array (TCMA). Our FILM array provides a unique solution to realize ultra-wideband tightly coupled apertures in the W and higher millimeter wave (mmWave) bands. The unit-cell architecture of the infinite FILM array is comprised of an inverted-L shaped monopole, and a capacitively coupled via-fence. This novel design eliminates the well-known broadside null from the radiation pattern of the traditional monopole element, and pushes both the common mode and loop mode resonances out of the band. To improve the impedance bandwidth and scanning ability, a dielectric-based superstrate is also used. The proposed array is extremely low profile with a maximum thickness of 0.4λ_H . Infinite array simulations of our array demonstrate a bandwidth of 3:1 (33 GHz to 101 GHz) with VSWR<3 for a maximum scan-angle of ±45 for all principal E-, H- and D-planes.
Chairs: Mark Fosberry, MITRE; Orin Henry, Georgia Tech Research Institute
1:30 PM – 128: A Wide-Angle Scanning Phased Array Antenna with Non-Reciprocal Butler Matrix Beamforming Network
Hamed Tadayon (INRS); Mansoor Dashti Ardakani (INRS University)*; Reza Karimian (The George Washington University); Shahrokh Ahmadi (The George Washington UThe theory and design of a wide scan array antenna is presented in this paper. A conventional 4×4 butler matrix is used to achieve four fundamental beam arrays from -45 degrees to +45 degrees. The use of Butler Matrix relaxes the requirement of the progressive phase and consequently the phase shifters to a good degree. The butler matrix is also integrated into a non-reciprocal feed network structure to achieve a non-reciprocal beamforming network with less complexity of the phase shifter and resolution requirements. The non-reciprocity is achieved through unidirectional amplifiers, different phase shifters with opposite progressive phases as well as a good Wilkinson power divider for isolation between the TX and RX paths. Two different progressive phases are also designed and shown here for the proof of concept. With one SP4T switch, and two passive low and high pass filters, eight different beam patterns were achieved four of them are for the transmit and the other four are for the receive paths. Any combination of the TX and RX paths can be used for different applications with a full-duplex scheme.
niversity); Mona Zaghloul (GWU)
1:50 PM – 133: A Wideband Non-Reciprocal Phased Array Antenna with Side Lobe Level Suppression
Hamed Tadayon (INRS University); Mansoor Dashti Ardakani (INRS University)*; Reza Karimian (The George Washington University); Shahrokh Ahmadi (The George Washington University); Mona Zaghloul (GWU)
A non-reciprocal antenna that can independently transmit and receive the signals in different directions is introduced in this paper. By using uni-directional amplifiers and different phase shifters a non-reciprocal antenna is achieved. Because the aperture of the antenna is the same for transmitting and receiving paths, the isolation between the two is important for practical applications. A non-uniform excitation by using a wideband feed-network microstrip structure improved the isolation between the two paths by more than 15 dB with an SLL suppression of better than 30 dB. Two different progressive phases by using low and high pass filters are shown for proof of concept. The concept can be applied for much smaller pattern resolution for space and commercial applications.
2:10 PM – 13: Beamforming with Uniform-Circular-Array and Ultrawideband-Throb Signal
Malek G. M. Hussain (Kuwait University)*
In this paper, the principle of beamforming using uniform circular array (UCA) antenna and ultrawideband (UWB)-throb signal is presented. The space-time resolution function of a UWB-throb signal received by a UCA antenna is derived and used to obtain the average-power beam pattern of the UCA. The elevation power pattern (EPP) and the azimuth power pattern (APP) for a UWB-throb signal and linear-frequency-modulated (LFM) signal, also referred to as chirp signal, received by a UCA are generated and compared. The EPP as well as the APP of the UWB-throb signal yield better angular resolution capability and have lower sidelobe levels than of he EPP and the APP of the LFM-chirp signal. It is shown that beam steering in the elevation plane of the UCA widens the beamwidth and influences the sidelobe structure of the power pattern, but not its general shape, while beam steering in the azimuth plane of the UCA is more robust and causes no deformation or widening of the power beampattern.
2:30 PM – 29: An Additively-Manufactured, Internally Metalized FUSE™ (IM-FUSE) Array
Eric Robinson (The MITRE Corporation)*; Franciso Ramos-Carrizosa (MITRE); Wajih Elsallal (MITRE); Carey Rappaport (Northeastern University)
In this paper, a new design technique is introduced which improves performance and lowers the fabrication cost of the Frequency-Scaled Ultra-Wideband Spectrum Element (FUSE™) aperture. The additively manufactured (AM) geometry is designed as a single block of polymer with hollow interior cavities corresponding to the radiating element shapes. An electroplating process is used to metalize only the interior surfaces of the cavities, enabling electrically isolated radiators with strong inter-element capacitive coupling. This technique results in a robust mechanical structure, eliminates the need for coaxial interposers, and utilizes low-cost plug-in connectors. The resulting simulated dual-polarized array achieves an active VSWR of 3.2:1 or less over a 7.3:1 frequency bandwidth while scanning to 60⁰ in in the E, H, and D scan planes with high Cross-Polarization Gain Isolation over most of the band.
2:50 PM – 154: Converged RF Phased Arrays Enabled by Silicon Photonics
Michael T Hoff (Lockheed Martin Corporation)*; Amit Kedia (Ayar Labs); Nhat Nguyen (Ayar Labs); Bob Paddison (Ayar Labs); Rick Stevens (Lockheed Martin Corporation)
This paper proposes a converged-aperture architecture to enable dynamic reconfiguration of spectral access between platform mission functions. Based on phased-array apertures, intra-platform data throughputs required to support the envisioned architecture are discussed, and integrated photonic transceivers are put forward as a critical enabling technology.
3:10 PM – 177: A PUMA Array Design for Space Applications
Thomas Hand (Lockheed Martin Space); Roger D Hasse (Lockheed Martin)*
This paper presents the design and experimental verification of a planar ultrawideband modular antenna (PUMA) antenna array intended for space applications. The low-profile, PCB design consists of linear, dual-polarized dipole elements that are arranged in a square lattice with offset phase centers. The PUMA array is optimized to achieve off-normal beam steering angles up to = 60 over a multi-octave bandwidth, and satisfies size, weight, and power (SWaP) requirements for future deployment on a space-based antenna array payload. The prototype PUMA array is designed to cover C-, X-, and Ku-bands. A prototype 15 15 dual-linear element array (225 elements, 25 connectorized) was designed, fabricated, and measured in a spherical near field range, where excellent agreement between modeled and measured radiation patterns are reported
3:30 PM – BREAK
4:00 PM – 30: Single-Polarization Vivaldi Antenna Array with Orthogonal Walls for Improved Polarization Purity
Rick Kindt (NRL)*; Jack Logan (NRL)
“Linearly polarized arrays of Vivaldi antennas are a common choice for ultra-wideband aperture implementations, often with a focus solely on bandwidth needs and less attention to polarization purity. With some forethought, it is possible to design Vivaldi antennas for low cross-polarization levels. In this paper, we highlight a simple approach to mitigate crosspolarization in two-dimensional array apertures of linearlypolarized Vivaldi antennas. This is demonstrated through a direct manufacturing approach that creates orthogonal metallic cross walls in arrays of all-metal linear Vivaldi flares. This demonstration has notable utility, as unlike dual-linear Vivaldi arrays, calibration of amplitude/phase via orthogonal channels cannot be used to correct polarization at a given frequency/angle in single-polarization Vivaldi arrays, as there are no orthogonal elements.”
4:20 PM – 31: Cross-Polarization Treatment in Linearly Polarized Vivaldi Array Apertures
Rick Kindt (NRL)*; Jack Logan (NRL)
“This paper examines how cross-polarization can be effectively reduced in two-dimensional array apertures of linearly-polarized Vivaldi antennas. In previous work it was demonstrated how metallic cross walls, positioned orthogonal to the linear Vivaldi antenna elements in a two-dimensional array, reduce cross-polarization significantly – e.g., -15dB levels for 45° diagonal plane scans. This cross-polarization mitigation technique is expanded upon by showing that slices in the metallic cross walls can further reduce cross-polarization, e.g. -25dB levels for 45° diagonal plane scans. For demonstration, an 8×8 single-pol. Vivaldi array comprising 8 rows of 8-element subarrays arranged onto a uniform grid with slots between elements is presented. Cross-polarization measurements are compared to infinite array simulations with and without ‘sliced’ metallic cards inserted (orthogonally) into the slots between radiating elements.”
4:40 PM – 119: A K- and V-Band Planar Dual-Polarized Tightly Coupled Dipole Array
Muhammad Hamza (Florida International University)*; Constantinos L. Zekios (Florida International University); Stavros Georgakopoulos (Florida International University)
A planar dual-polarized ultra-wideband array that covers both K and V bands is presented. The architecture relies on tightly coupled dipoles arranged in an egg-crate configuration and a novel capacitive via arrangement that pushes both, the common mode resonance and, the detrimental loop mode resonance, out of the band. To improve the impedance bandwidth and scanning ability, a Marchand balun feed network and a dielectric-based superstrate are respectively used. Infinite array simulations of our array demonstrate a bandwidth of 2.85:1 (22.25GHz to 64GHz) with VSWR<3 for a maximum scan-angle of ±45 for both E- and H-planes.
5:00 PM – 34: A Study of Uniformly Excited Linear Phased Array for Wideband Operation
Yu Ping Liu (Oakland University)*; Amanpreet Kaur (Oakland University)
In this paper a simple and intuitive equation is developed for a uniformly excited linear phased array for wideband frequency operation. This equation unifies phase delay, time delay, antenna element spacing, and operating frequency. Most importantly, the equation shows the array pattern can be normalized and multiplied into its final implementation of any frequency. This means existing array factors in use can be applied to a new design at any frequency. The equation is demonstrated with 3 possible real-world applications. The array pattern is first calculated using the expanded wideband equation and then verified using HFSS using a wideband linear tapered slot antenna for each design. In 2 of the examples, calculation and verification are done at 2 different bands to demonstrate the analysis is indeed normalized and can be multiplied into different frequency bands. The last example shows how the equation calculates element spacing to compensate for a squint-free phased array operating in wideband, which is easily achievable with Active Electronically Scanned Arrays (AESA). The equation provides an intuitive understanding of phased array characteristics in wideband, and it simplifies the design process, hopefully paving the way for further development of phased array systems.