Phased Array Radar Applications Research Articles

Dual Polarized Array Antenna for S/X Band Active Phased Array Radar Application

A dual-band dual-polarized microstrip antenna array for an advanced multi-function radio function concept (AMRFC) radar application operating at S and X-bands is proposed. Two stacked planar arrays with three different thin substrates (RT/Duroid 5880 substrates with e r =2.2 and three different thicknesses of 0.253 ㎜, 0.508 ㎜ and 0.762 ㎜) are integrated to provide simultaneous operation at S band (3～3.3 ㎓) and X band (9～11 ㎓). To allow similar scan ranges for both bands, the S-band elements are selected as perforated patches to enable the placement of the X-band elements within them. Square patches are used as the radiating elements for the X-band. Good agreement exists between the simulated and the measured results. The measured impedance bandwidth (VSWR≤2) of the prototype array reaches 9.5 % and 25 % for the S- and X-bands, respectively. The measured isolation between the two orthogonal polarizations for both bands is better than 15 ㏈. The measured cross-polarization level is ≤?21 ㏈ for the S-band and ≤?20 ㏈ for the X-band.

A 3-D X-Band T/R Module Package With an Anodized Aluminum Multilayer Substrate for Phased Array Radar Applications

This paper presents the design and development of a compact 3-D transmit/receive (T/R) module with a selectively anodized aluminum multilayer package for X-band phased array radar applications. The proposed multilayer package consists of anodized aluminum substrates and vertical interconnects with embedded vias. The proposed package platform is based on thick anodized aluminum oxide layers and active bare chips directly mounted on bulk aluminum substrates for high electrical isolation and an effective heat sink. With its combination of thin-film embedded passive components and multilayer structure, the proposed module features a compact size of 20 mm × 20 mm, with a package height of 3.7 mm. To transfer radio-frequency (RF) signals vertically, we used coaxial hermetic seal vias with characteristic 50 Ω impedances and embedded anodized aluminum vias with a solder ball attachment and flip-chip bonding. The optimized vertical interconnect structure demonstrates RF characteristics with an insertion loss of less than 1.55 dB and a return loss of less than 12.25 dB over a broad bandwidth ranging from 0.1 to 10 GHz. The fabricated X-band 3-D T/R module has a maximum transmit output power of 39.81 dBm (9.5 W), a maximum transmit gain of 41.25 dB, and a receive gain of 19.15 dB over the 9-10 GHz frequency band. The RF-signal phase amplitude control is achieved by means of a 6 bit phase shifter with an rms accuracy of more than 5° and a gain setting range of 24 dB with an rms accuracy of more than 1.5 dB. The proposed multilayer aluminum package has the advantages of reducing the module size, decreasing the cost, and managing the thermal problem for X-band high-power T/R module package applications.

Reduced-Rank STAP Schemes for Airborne Radar Based on Switched Joint Interpolation, Decimation and Filtering Algorithm

In this paper, we propose a reduced-rank space-time adaptive processing (STAP) technique for airborne phased array radar applications. The proposed STAP method performs dimensionality reduction by using a reduced-rank switched joint interpolation, decimation and filtering algorithm (RR-SJIDF). In this scheme, a multiple-processing-branch (MPB) framework, which contains a set of jointly optimized interpolation, decimation and filtering units, is proposed to adaptively process the observations and suppress jammers and clutter. The output is switched to the branch with the best performance according to the minimum variance criterion. In order to design the decimation unit, we present an optimal decimation scheme and a low-complexity decimation scheme. We also develop two adaptive implementations for the proposed scheme, one based on a recursive least squares (RLS) algorithm and the other on a constrained conjugate gradient (CCG) algorithm. The proposed adaptive algorithms are tested with simulated radar data. The simulation results show that the proposed RR-SJIDF STAP schemes with both the RLS and the CCG algorithms converge at a very fast speed and provide a considerable SINR improvement over the state-of-the-art reduced-rank schemes.

Design of X‐band 6‐bit CMOS phase shifter for phased array T/R modules

AbstractThis article presents the design of a 6‐bit phase shifter in a 0.18‐μm CMOS technology for X‐band phased array radar application. Meandered microstrip lines and compact circuit designs techniques yield a chip with 1.9 mm2 die area. The fabricated phase shifter demonstrates a typical 15.7 ± 1.1 dB insertion loss and a 4° rms phase shift error at 9.5 GHz. To the author's knowledge, this is the first demonstration of a 6‐bit phase shifter using CMOS switches with the lowest die area among reciprocal digital phase shifters at X‐band. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2404–2406, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24663

Broad-band SiGe MMICs for phased-array radar applications

This paper reports the performances of several broad-band monolithic SiGe monolithic microwave integrated circuits (MMICs) suitable for phased-array radar applications. The amplitude and phase control MMIC designs are based on an optimized SiGe p-i-n diode offered by the IBM 5HP SiGe foundry process. Utilizing this diode, several control circuitries including a broad-band (1-20-GHz) monolithic single-pole double-throw switch, a five-port transfer switch, a 6-bit phase shifter, and a 5-bit attenuator, all operating over 7-11 GHz, are designed. Also, the design and performance of an SiGe heterojunction bipolar transistor variable-gain cascode amplifier that combines the functionality of an amplifier and an attenuator into one MMIC is described.

A 32-element 8-bit photonic true-time-delay system based on a 288 x 288 3-D MEMS optical switch

A large-scale three-dimensional microelectromechanical-system optical switch is used for the first time to realize a true-time-delay (TTD) beamformer for phased-array radar applications, with a capacity of 32 antenna elements and eight bits of delay. The 288 /spl times/ 288 optical switch has a median loss of 1.4 dB and all measured 82 944 paths exhibit less than 2.3 dB loss at 1310 nm. The TTD beamformer exhibits a loss variation of 1.5 dB, which is equalized using a mirror-offset technique.

Robust space-time adaptive processing for airborne radar in nonhornogeneous clutter environments

Space-time adaptive processing (STAP) holds tremendous potential for the new generation airborne surveillance radar, in which the phased array antennas and pulse Doppler processing mode are adopted. A new STAP approach using the multiple-beam and multiple Doppler channels is presented here for airborne phased array radar. The approach with space-time multiple-beam (STMB) architecture is robust to array errors and has very low system degrees of freedom (DOFs). Hence, it has low sample support requirement and it is very suitable for the practical planar phased array radar under nonhomogeneous clutter environments. Meanwhile, a new nonhomogeneous detector (NHD) based on the correlation dimension (CD) is also proposed here, which is used as an effective method to screen tracing data prior to detection processing. It can further improve the performance of the STAP approach in the severely nonhomogeneous clutter environments. Therefore, a scheme that incorporates the correlation dimension nonhomogeneity detector (CD-NHD) with the STMB is recommended, which we term CD-NHD-STMB. The experimental simulation results indicate that: 1) the STMB processor is robust to array element error and has high performance under nonhomogeneous clutter environments; 2) the CD-NHD is also effective on the nonhomogeneous clutter. As a result, the CD-NHD-STMB scheme is robust to array element error and nonhomogeneous clutter, and therefore available for airborne phased array radar applications.

A framework of rank-reduced space-time adaptive processing for airborne radar and its applications

A new equivalent formulation of the joint domain space-time optimum processor for airborne phased array radar application is derived. Then a new framework of space-time adaptive processing (STAP) for airborne radar systems which includes most of suboptimum algorithms in the literature is proposed. The performance of two typical rank-reduced time-space joint-domain processors based on Doppler pre-filtering is analyzed in detail based on the proposed framework.

Multihypothesis tracking with electronically scanned radar

Multihypothesis tracking (MHT) methods, well known for conventional radar data-processing, are generalized for phased-array radar application. We consider single targets in a cluttered environment. Suitable revisit and beam positioning algorithms are derived and optimized regarding the energy spent for tracking. In particular the destabilization of tracks due to clutter interference is analyzed. A comparison with a conventional algorithm (probabilistic data association filter (PDAF)) shows the saving of radar load which can be achieved by the proposed method.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Ferroelectric phase shifters for phased array radar applications

Abstract The traditional rotating reflector antenna associated with airport traffic control systems is being replaced in some applications by a new design concept called the phased array. Generally planar in shape, it is made up of thousands of closely spaced, individual radiators whose composite beam can be shaped and spacially directed in microseconds, enabling it to track a multitude of targets at one time. This is accomplished electronically by RF phase shifters associated with each individual radiating element. No moving parts are required. State of the art, passive phased array antennas are limited in their application by cost, more than any other factor. Even utilizing the latest technology and fabricating techniques, the required phase shifters are not cheap, and with a typical array requiring thousands of individual antenna elements, each with its own phase shifter, the price of the total system quickly becomes prohibitive.

X-band MIC GaAs IMPATT amplifier module

A compact (2.0 by 1.6 in), light weight (2.1 oz), microwave integrated circuit (MIC) GaAs IMPATT amplifier module having 3.6-W pulsed output power with a gain of 22.5 dB over the 9.2-9.8 GHz band has been developed for phased array radar applications. The design goal for the module was 4-W pulsed output power with 23-dB gain over this frequency band. The module has been operated over a wide range of pulse lengths (200 ns-50 /spl mu/s) and duty factors (0.5-40 percent) with outstanding pulse fidelity. The totally integrated module consists of three IMPATT reflection amplifier stages in cascade with input and output isolators and a transmit/receive switch. Each amplifier stage has an independent hybrid thin film constant current pulse modulator. The design considerations of the essential components for final module integration, and the microwave performance characteristics are presented.

Packaging an X-band microwave integrated circuit

Packaging of a hermetically sealed X-band microwave integrated circuit module is described. The module is a complete receiver-transmitter, including dipole antenna, for phased array radar applications. The principal problem areas are: 1. Interconnections between microwave thin film ceramic circuit units within the module. 2. Mechanical space limitations, imposed largely by wavelength considerations. 3. Techniques for mounting the ceramic circuit units within the module. 4. External geometry which affects mounting and external connections. 5. Dissipation of heat.