Phased Array Radar Applications Research Articles

A Low Cross-Polarization Microstrip Antenna Array for Millimeter Wave Applications

A low cross-polarization microstrip antenna array for millimeter wave (mmW) applications is proposed in this paper. The antenna element is composed of symmetric T-shaped patches with vias. The adoption of a double-sided symmetric radiation patch structure can suppress the cross-polarized electric field, and the vias reduces energy leakage during the power transmission along the antenna patches. To verify the concept, a 1 × 8 antenna array is fabricated and measured. The measured −10 dB impedance of the antenna array is 28.4% (31 GHz–41.5 GHz) and the peak gain is 15 dBi. The cross polarization ratio is above 35 dB and the 3 dB beamwidths on E-plane and H-plane are 7.5° and 135°, respectively. The proposed compact size and low cross-polarization antenna array might be a good choice for phased array radar and 5th generation (5G) mobile communication applications.

A Method for Rapid Measurement of the Deformation and Spatial Attitude of Large Radar Antennas Inside Radomes

It is challenging to measure, analyze, and control the deformation and space attitude of antennas in narrow radomes through geometric measurement to ensure the accuracy of phased array radar application. In this manuscript, a method for rapid measurement of antennas by adopting the combination of photogrammetry system, laser tracker and total station was proposed. The photogrammetric method was used with a homemade auxiliary tool to measure and calculate the antenna’s deformation under different temperatures and pitch angles. Mapping relations between the instrumental coordinate systems of photogrammetry system, laser tracker and total station were established through common points, including target balls and reflectors. Coordinates of mark points on antenna surface were converted from photogrammetric coordinate system to laser tracker’s and total station’s coordinate system. Thus, antenna’s pitch angles relative to the local horizontal plane and deflection angles relative to the north of the engineering coordinate system were calculated. Planar fitting, coordinate transformation and space attitude calculation were all carried out in the Spatial Analyzer (SA) software. The photogrammetric method detected the antenna’s gravitational deformation sensitively, the maximum Root Mean Square Residual (RMSR) of the reference length was $54~\mu \text{m}$ , and that of the mark points was $59~\mu \text{m}$ , which was stably in line with its nominal accuracy. Deviations caused by coordinate transformation had no significant effect on the calculation of antenna’s spatial attitude, for the maximum deviation between the converted and measured coordinates in laser tracker’s coordinate system was 0.139 mm, and that in total station’s coordinate system was 1.037 mm, both of which were within reasonable limits of the derived theoretical maximum deviations between different instruments. As a result, the maximum deviation between the calculated value and servo system’s nominal value of antenna’s pitch angle was $59.4''$ , and that of antenna’s deflection angle was $91.87''$ . This method’s efficiency was greatly improved by about ten times compared with traditional methods through statistics and estimates.

A Fully Integrated K-Band Dual Down-Conversion Receiver for Radar Applications in 90 nm CMOS

A fully integrated K-band dual down-conversion receiver for phased array radar applications in 90 nm CMOS is presented. The receiver utilizes the dual down-conversion architecture to achieve superior performance. The integrated 1.15 GHz image-rejection filter (IRF) provides enough wideband (22 MHz) image rejection ratio at 140 MHz offset before the second down-conversion by utilizing the Q-enhancing and frequency staggering techniques to compensate the component loss. The low noise amplifier realizes the single-to-differential-ended conversion at the input with a transformer and achieves good common-mode rejection. The 70 MHz intermediate frequency baseband consists of two cascaded 3rd-order band-pass active RC filters (BPFs) and one automatic gain control (AGC) loop, with the integrator frequency compensation technique to lower down the requirements on the embedded Op-Amps. Two phase-locked loop (PLL) frequency synthesizers are integrated to provide the local oscillation (LO) signals for the down-conversions, where the matching of the charge-pump is improved by adding one extra current compensation branch. The measurements of the prototype show that the receiver converts the targeted mm-wave signal to 70 MHz intermediate frequency while achieving 8.3 dB noise figure (NF), 51-95 dB variable gain range and >45 dB image rejection ratio at 140 MHz offset with >22 MHz signal bandwidth. The receiver draws 74 mA current (excluding 2 PLLs) from the 1.2 V power supplies and occupies a core area of 4.58 × 0.53mm 2 (excluding 2 PLLs).

Frequency Agile Microstrip Patch Antenna Using an Anisotropic Artificial Dielectric Layer (AADL): Modeling and Design

This paper presents the modeling and design of a frequency agile antenna using an anistropic artificial dielectric layer (AADL) for multi-band phased array radar applications. The proposed AADL material is placed underneath the patch radiator and is designed using periodically arranged metallic cylinders in which varying height, diameter, and the distance used between them allows the control of the effective permittivity of the patch antenna. Closed form design expressions are formulated to synthesize the dielectric properties of the AADL as a function of the cylindrical unit cell dimensions. Design trade-offs based on the proposed formulation and numerical simulations show the overall performance of the AADL on microstrip patch (MS) antennas. To validate the proposed concept, five individual AADL MS patch antennas in C-band were designed, fabricated, and tested. Simulated and measured results ( ${s}$ -parameters and radiation patterns) are in good agreement with the results obtained from the theoretical model. The proposed AADL concept has the potential to be used in the development of future reconfigurable tunable multiband antennas that use liquid metal to dynamically change the heights of the cylinders.

A 2×2 Antenna Array for X Band Phased Array RADAR Applications

A Four element rectangular patch antenna array has been designed for the Phase array RADAR applications in the X Band with an operating frequency of 10GHz. The four patches are been connected to four different transmitter circuit with which we can control the phase of the input signal. A 50Ω coaxial probe feed has been used to excite the antenna. The overall dimension of the antenna is 212mm×212mm×1.6mm. The Proposed antenna is having an gain of 10.2dB at the operating frequency of 10GHz. The directivity of the antenna at the operating frequency is 10.31dB. Low cost FR4 material is been used as the laminate base for the antenna which will act as the dielectric material.

A 2×2 Antenna Array for X Band Phased Array RADAR Applications

A Four element rectangular patch antenna array has been designed for the Phase array RADAR applications in the X Band with an operating frequency of 10GHz. The four patches are been connected to four different transmitter circuit with which we can control the phase of the input signal. A 50Ω coaxial probe feed has been used to excite the antenna. The overall dimension of the antenna is 212mm×212mm×1.6mm. The Proposed antenna is having an gain of 10.2dB at the operating frequency of 10GHz. The directivity of the antenna at the operating frequency is 10.31dB. Low cost FR4 material is been used as the laminate base for the antenna which will act as the dielectric material.

A 2×2 Antenna Array for L Band Phased Array RADAR Applications

A Four element antenna array for the Phase array RADAR applications in the L Band with an operating frequency of 1.32GHz is presented. The four patches are been connected to four different transmitter circuit with which we can control the phase of the input signal. The antenna is having a size of 212mm×212mm×1.6mm with a gain of 8.78dB and directivity of 10.31dB at the operating frequency of 1.32GHz.. Low cost FR4 material is been used as the laminate base for the antenna which will act as the dielectric material.

A 2×2 Antenna Array for L Band Phased Array RADAR Applications

A Four element antenna array for the Phase array RADAR applications in the L Band with an operating frequency of 1.32GHz is presented. The four patches are been connected to four different transmitter circuit with which we can control the phase of the input signal. The antenna is having a size of 212mm×212mm×1.6mm with a gain of 8.78dB and directivity of 10.31dB at the operating frequency of 1.32GHz.. Low cost FR4 material is been used as the laminate base for the antenna which will act as the dielectric material.

A Tunable SiGe BiCMOS Gain-Equalizer For X-Band Phased-Array RADAR Applications

This brief presents a compact-size tunable gain-equalizer for X-band phased-array RADAR applications in a 0.25- $ \mu \text{m}$ SiGe BiCMOS technology. An isolated nMOS-based variable resistance was used for the first time to tune the slope of the gain-equalizer. For nMOS, an isolated body created by a deep n-well was utilized to reduce insertion loss due to the substrate conductivity. Furthermore, the power-handling capability of the tunable gain-equalizer was improved thanks to the resistive body-floating technique. The designed tunable gain-equalizer operates in the frequency range from 8 to 12.5 GHz with a measured positive slope of 1 dB/GHz and 1 dB tunable slope. The effective chip area excluding the pads is 0.21 mm2, and the total area including pads is 0.31 mm2. To authors best knowledge, this brief is the first tunable gain-equalizer in SiGe technology presented for X-band phased-array RADAR applications.

High-Isolation, Low Cross-Polarization, Dual- Polarization, Hybrid Feed Microstrip Patch Array Antenna for MPAR Application

This paper presents a high-isolation, low cross-polarization dual-polarized patch antenna for multifunction phased array radar applications. Its hybrid feed design has been implemented, and the vertical and horizontal polarizations are excited by a balanced-probe feed and a slot-coupled feed, respectively. Simulations and measurements have demonstrated an input isolation of 45 and 43 dB between the horizontal and vertical ports, respectively. For further improvement in the cross-polarization level, the image feed method is also implemented, and a $2\times 2$ -element array made up of designed elements with image configuration has been fabricated. The simulated and measured S-parameter and radiation patterns of the horizontal and vertical polarizations of the designed $2\times 2$ -element array are presented and the measured cross-polarization level of less than −37 dB is achieved. To examine the performance of the designed element in an array, a $3\times 3$ -element array of designed $2\times 2$ -element subarray is fabricated and tested. In the $6\times 6$ -element measurements, −35.4 and −36 dB cross-polarization levels for horizontal and vertical polarizations are achieved, respectively. Also, using the measured embedded element patterns, the cross-polarization level lower than −36 dB for scan angles up to 45° is achieved.

Cognate pulse sorting method based on beam missions characteristics

In most multi-function phased array radar applications, multiple missions, including airspace searching and target tracking, are usually performed simultaneously by the digital beam-forming technique and the time dividing method. This paper presents a novel method to classify pulses of different missions from an interleaved pulse sequence emitted by the same radar, which is significant in radar electronic reconnaissance and electronic support measure. Firstly, two hypotheses, i.e., pulse relativity within the same mission and pulse independence among different missions, are proposed by analyzing the antenna pattern and the beam scheduling method of the phased array radar. Based on the above two hypotheses, an optimal model for pulse classification is exploited with pulse amplitude series, where the absolute-value sum of second order difference is taken as the optimal kernel to measure sequence smooth continuity. Finally, several pieces of sequences under different numbers of missions and tracking data rates are simulated for algorithm verification. The simulation results show that the long data length and the high data rate will increase classification efficiency due to the validity of the two hypotheses in sufficient pulse amplitude sequence.

Compact Printed Dipole Antenna for L- Band Radar Applications

This paper presents the design and analysis of a compact microstirp fed wide band printed dipole antenna operating in L band. The dipole antenna bandwidth is improved by flaring of dipole arms, tapering ground plane, and the best impedance matching is achieved by introducing an open circuited stub with dipole arm. Parametric study is carried out to study the effect of dipole length and arm width on the antenna resonant frequency and bandwidth has also been investigated. The antenna is printed on FR4 substrate and the simulated return loss bandwidth is validated by the measured result. The fabricated antenna provides a wide bandwidth of 51.2% at the centre frequency of 1.3 GHz and the peak gain of 3.2 dB which is suitable for phased array radar applications.

X‐band SiGe bi‐complementary metal–oxide semiconductor transmit/receive module core chip for phased array RADAR applications

This study presents a transmit/receive (T/R) module core chip with 4-bit operation using 0.25 µm silicon–germanium (SiGe) bi-complementary metal–oxide semiconductor (BiCMOS) technology, for X-band phased array RADAR applications. The T/R module core chip consists of sub-blocks such as low noise amplifier, power amplifier, phase shifter, single-pole double-throw switch and variable gain amplifier. Switches incorporate n-type MOS devices while amplifiers are implemented with SiGe heterojunction bipolar transistors. Measurement results for the complete core chip and its individual sub-blocks are reported here. Between 9 and 10 GHz, the constructed T/R module achieves about 11 dB gain for both receiver (RX) and transmitter (TX) chains, while it has −10.5 dBm receiver chain third-order intermodulation intercept point (IIP3), and 16 dBm OP1 dB for transmitter chain. Root-mean-square phase error is measured as 5, whereas noise figure varies between 4 and 6 dB. The total power dissipation of core chip is about 285 mW, with a total area of 4.9 mm2.

Life test of an X-band MMIC multi-function chip for active phased array radar applications

A 1000-h steady state life test at a temperature of 125°C was performed on ten X-band MMIC multifunction chips for use in active phase array radar systems. Internal switches, phase shifters, and attenuators were operated through an integrated serial-to-parallel converter under the five-second stepped external control signal for the life test period. None of the ten samples failed under the failure criteria based on the JEP118 standard. The calculated failure rate using the Chi Square Statistic was 1.6e−6 failures/h for the 90% confidence level. Maximum DC current variation was +16% for an initial value. Maximum variations of small signal gain, phase shift, and attenuation were 0.96dB, 2°, and 0.17dB, respectively, over a frequency range of 8.5–10.5GHz.

An X-Band Slow-Wave T/R Switch in 0.25-$\mu\hbox{m}$ SiGe BiCMOS

This brief presents a fully integrated X-band transmit/receive (T/R) switch using slow-wave transmission lines for X-band phased-array radar applications. The T/R switch was fabricated in a 0.25- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\mu\hbox{m}$</tex></formula> SiGe bipolar CMOS (BiCMOS) process and occupies 0.73- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{mm}^{2}$</tex></formula> chip area, excluding pads. The switch is based on shunt–shunt topology and employs isolated n-channel (NMOS) transistors and slow-wave microstrip lines. Additionally, resistive body floating and dc biasing are employed to improve the power-handling capability <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({P}_{1\, {\rm dB}})$</tex></formula> of the switch. The T/R switch resulted in a measured insertion loss of 2.1–2.9 dB and isolation of 39–42 dB from 8 to 12 GHz. The input referred <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${P}_{1\, {\rm dB}}$</tex></formula> is 27.6 dBm at 10 GHz. To our knowledge, this brief presents the utilization of slow-wave transmission lines in T/R switches for the first time. Furthermore, it can simultaneously satisfy stringent isolation, insertion loss, and power-handling capability requirements for implementing a fully integrated SiGe T/R module.

Integrated Design of a Compact and Lightweight S-Band Traveling-Wave Tube Amplifier for a New Class of Microwave Power Module

A new class of compact and lightweight S-band 1 kW traveling-wave tube (TWT) is being developed for a microwave power module (MPM) that will be used for phased antenna array radar applications. The proposed S-band MPM provides a tenfold peak power increase compared to state-of-the-art S-band MPMs. In this paper, the design of the vacuum power booster TWT part of the MPM is presented. The compact and lightweight S-band TWT is driven by a 6 kV, 0.9 A electron beam. The amplifier is predicted by large-signal simulations to generate over 1 kW at S-band with 25 dB saturated gain and over 40% efficiency. The stability from unwanted oscillations has been investigated. To suppress the oscillations, the helix circuit has been coated with carbon composite material. The coaxial input and output antennas have been fabricated. For efficiency enhancement, a multi-stage depressed collector (MDC) has been designed using a 3D particle-in-cell (PIC) simulator, VORPAL. The collector design makes use of a current loop based on a feedback mechanism for effective design process. The integrated designs of a helix circuit, an electron gun, a periodic permanent magnet (PPM), antennas, and a collector are presented.

A fully integrated, highly linear CMOS T/R switch for X‐Band phased array radars

AbstractThis paper presents the design and implementation of a single‐pole, double‐throw transmit/receive (T/R) switch for X‐Band (8–12 GHz) phased array radar applications. The T/R switch was fabricated in a 0.25‐µm SiGe BiCMOS process and occupies 0.44‐mm2 chip area, including pads. The design focuses on the techniques, primarily, to achieve higher power handling capability (P1dB), along with higher isolation and better insertion loss (IL) of the T/R switch. These techniques include resistive‐body floating, using on‐chip impedance transformation networks and DC biasing of all terminals of the T/R switch. In addition, optimization of transistor widths and parallel resonance technique are used to improve IL and isolation, respectively. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 34.8 dB and IP1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this paper presents the single‐ended CMOS T/R switch with the highest IP1dB, competitive isolation and comparable IL at X‐Band, compared to other reported works in the literature and attributed to the unique design methodologies and techniques. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Compact X-band SiGe power amplifier for single-chip phased array radar applications

An X-band power amplifier (PA) is presented for single-chip phased array radar applications. In this work, the choice of optimum circuit topology for X-band PA design is discussed and possible stability issues for high and low frequencies are analysed. The PA features a two-stage cascode architecture that includes both high-speed (low breakdown) and high breakdown (low-speed) SiGe transistors. It consists of two stages providing a 23.2 dBm saturated output power with a 28% power-added efficiency at 9 GHz. The output 1-dB compression point (P1dB) is higher than 20 dBm in a 3 GHz bandwidth and has a maximum value of 22.2 dBm. The small-signal gain is 25.5 dB with a 3-dB bandwidth of 3.2 GHz (7.3–10.5 GHz). The PA has been fabricated using 0.25 µm SiGe BiCMOS process provided by IHP Microelectronics. The PA occupies 1 mm×0.6 mm chip area and consumes 120 mA from a 4 V supply voltage. These results demonstrate comparable or better performance than other reported PAs and suitable performance for single-chip phased array applications.

X-band, high performance, SiGe-heterojunction bipolar transistors-low noise amplifier for phased array radar applications

This study presents an X-band low noise amplifier (LNA) implemented in 0.25 µm SiGe BiCMOS process aiming for phased array radar applications. The LNA is composed of two cascode stages using SiGe heterojunction bipolar transistors to achieve low noise figure, high gain and a better matching to 50 Ω at the input and output, simultaneously. The first stage is designed for low noise performance whereas the second stage is optimised to improve the input third-order intercept point (IIP3). The LNA resulted in a measured gain of 21 dB, a noise figure of 1.52 dB and an IIP3 of −8 dBm at 10 GHz. The active chip area without pads is 620×820 µm2 and the power dissipation is 22 mW from a 2.2 V power supply. These performance parameters collectively constitute the best figure-of-merit value of 101, reported in similar technologies.

Sparsity-aware space–time adaptive processing algorithms with L1-norm regularisation for airborne radar

This study proposes novel sparsity-aware space–time adaptive processing (SA-STAP) algorithms with L1-norm regularisation for airborne phased-array radar applications. The proposed SA-STAP algorithms suppose that a number of samples of the full-rank STAP datacube are not meaningful for processing and the optimal full-rank STAP filter weight vector is sparse, or nearly sparse. The core idea of the proposed method is imposing a sparse regularisation (L1-norm type) to the minimum variance STAP cost function. Under some reasonable assumptions, the authors firstly propose an L1-based sample matrix inversion to compute the optimal filter weight vector. However, it is impractical because of its matrix inversion, which requires a high computational cost when using a large phased-array antenna. In order to compute the STAP parameters in a cost-effective way, the authors devise low-complexity algorithms based on conjugate gradient techniques. A computational complexity comparison with the existing algorithms and an analysis of the proposed algorithms are conducted. Simulation results with both simulated and the Mountain-Top data demonstrate that fast signal-to-interference-plus-noise-ratio convergence and good performance of the proposed algorithms are achieved.