New miniature 15-20-GHz continuous-phase/amplitude control MMICs using 0.18-/spl mu/m CMOS technology

The design and performance of two new miniature 360/spl deg/ continuous-phase-control monolithic microwave integrated circuits (MMICs) using the vector sum method are presented. Both are implemented using commercial 0.18-/spl mu/m CMOS process. The first phase shifter demonstrates all continuous phase and an insertion loss of 8 dB with a 37-dB dynamic range from 15 to 20 GHz. The chip size is 0.95 mm /spl times/ 0.76 mm. The second phase shifter can achieve all continuous phase and an insertion loss of 16.2 dB with a 38.8-dB dynamic range at the same frequency range. The chip size is 0.71 mm /spl times/ 0.82 mm. To the best of the authors' knowledge, these circuits are the first demonstration of microwave CMOS phase shifters using the vector sum method with the smallest chip size for all MMIC phase shifters with 360/spl deg/ phase-control range above 5 GHz reported to date.     

Distributed 2- and 3-bit W-band MEMS phase shifters on glass substrates

This paper presents state-of-the-art RF microelectromechanical (MEMS) phase shifters at 75-110 GHz based on the distributed microelectromechanical transmission-line (DMTL) concept. A 3-bit DMTL phase shifter, fabricated on a glass substrate using MEMS switches and coplanar-waveguide lines, results in an average loss of 2.7 dB at 78 GHz (0.9 dB/bit). The measured figure-of-merit performance is 93/spl deg//dB-100/spl deg//dB (equivalent to 0.9 dB/bit) of loss at 75-110 GHz. The associated phase error is /spl plusmn/3/spl deg/ (rms phase error is 1.56/spl deg/) and the reflection loss is below -10 dB over all eight states. A 2-bit phase shifter is also demonstrated with comparable performance to the 3-bit design. It is seen that the phase shifter can be accurately modeled using a combination of full-wave electromagnetic and microwave circuit analysis, thereby making the design quite easy up to 110 GHz. These results represent the best phase-shifter performance to date using any technology at W-band frequencies. Careful analysis indicates that the 75-110-GHz figure-of-merit performance becomes 150/spl deg//dB-200/spl deg//dB, and the 3-bit average insertion loss improves to 1.8-2.1 dB if the phase shifter is fabricated on quartz substrates.     

2.4 GHz continuously variable ferroelectric phase shifters using all-pass networks

Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub min/) of a BST interdigital capacitor is over 2.9 with a bias voltage of 140 V. The phase shifter provides more than 121/spl deg/ phase shift with the maximum insertion loss of 1.8 dB and the worst case return loss of 12.5 dB from 2.4 GHz to 2.5 GHz. By cascading two identical phase shifters, more than 255/spl deg/ phase shift is obtained with the maximum insertion loss of 3.75 dB. The loss figure-of-merit of both the single- and double-section phase shifters is over 65/spl deg//dB from 2.4 GHz to 2.5 GHz.     

A new active RF phase shifter using variable gain, drain Voltage controlled PHEMTs:A 2.4-GHz ISM implementation

Phase shifters operating at RF bands are an essential component of phased and adaptive arrays circuits. In this letter, an active phase shifter is proposed, using vector summing of an in-phase and a quad-phase replica of the incoming signal. The proposed scheme was designed and implemented using a Wilkinson power combiner/divider, a branch line hybrid coupler and single-stage variable gain amplifiers (VGAs), achieving continuous phase shift within the range of [0/spl deg/, 90/spl deg/]. The manufactured prototype is suitable for WLAN operations in the 2.4-GHz ISM band. Details of the phase shifter design and experimental results are presented.     

A 77-GHz MMIC power amplifier for automotive radar applications

A MMIC 77-GHz two-stage power amplifier (PA) is reported in this letter. This MMIC chip demonstrated a measured small signal gain of over 10 dB from 75 GHz to 80 GHz with 18.5-dBm output power at 1 dB compression. The maximum small signal gain is above 12 dB from 77 to 78 GHz. The saturated output power is better than 21.5 dBm and the maximum power added efficiency is 10% between 75 GHz and 78 GHz. This chip is fabricated using 0.1-/spl mu/m AlGaAs/InGaAs/GaAs PHEMT MMIC process on 4-mil GaAs substrate. The output power performance is the highest among the reported 4-mil MMIC GaAs HEMT PAs at this frequency and therefore it is suitable for the 77-GHz automotive radar systems and related transmitter applications in W-band.     

A coplanar X-band AlGaN/GaN power amplifier MMIC on s.i. SiC substrate

This work presents a two-stage high-power amplifier monolithic microwave integrated circuit (MMIC) operating between 9 GHz and 11 GHz based on a fully integrated AlGaN/GaN high electron mobility transistor (HEMT) technology on s.i. SiC substrate and is suitable for radar applications. The MMIC device with a chip size of 4.5/spl times/3 mm/sup 2/ yields a linear gain of 20 dB and a maximum pulsed saturated output power of 13.4 W at 10 GHz equivalent to 3.3 W/mm at V/sub DS/=35V, 10% duty cycle, and a gain compression level of 5 dB. Further, dc reliability data are given for the MMIC HEMT technology.     

Wide-band photonically phased array antenna using vector sum phase shifting approach

In this paper, a wide-band photonically phased array antenna is demonstrated. The array configuration consists of a 4 /spl times/ 1 Vivaldi single-polarization antenna array and an independent photonic phasing system for each element. The phasing network of this array is implemented using two novel photonic phase shifters based on the vector summation approach. A vector sum phase shifter (VSPS), which exhibits a frequency-linear characteristic from dc to 15 GHz and can be continuously tuned from 0 to 100/spl deg/, is presented. A second-order VSPS (SO-VSPS), a modification of the VSPS that is capable of 0-430/spl deg/ phasing range, is also demonstrated. This paper presents the operation and characterization of each component of the array, including the radiating elements and the various photonic phase shifters and, finally, a demonstration of the combined system. A discussion on the practicality of this system for airborne applications is presented, along with suggestions for simplification and improvement.     

Continuous Varactor-Diode Phase Shifter with Optimized Frequency Response

A method is introduced for designing continuous varactor-diode phase shifters with optimum frequency response. The circuit used gives very small frequency variations of the phase shift if the maximum phase shift of the device is less than about 200/spl deg/. Measurement results on a 180/spl deg/ L-band phase shifter are presented. This unit gives less than 5/spl deg/ variation of any given phase shift less than 180/spl deg/, when the frequency is changed from 1.5 to 1.7 GHz.     

RF MEMS phase shifters based on PCB MEMS technology

An X-band main-line type loaded line RF MEMS phase shifter fabricated using printed circuit based MEMS technology is reported. The phase shifter provides a phase shift of 31.6/spl deg/ with a minimum insertion loss of 0.56 dB at 9 GHz for an applied DC bias voltage of 40 V. These phase shifters are suitable for monolithic integration with low-cost phased arrays on Teflon or Polyimide such as low dielectric constant substrates.     

毫米波数控移相器的设计与制作

移相器是毫米波相控阵雷达收发系统重要电路,基于安捷伦IC-CAP软件及砷化镓原片工艺线,研究了砷化镓毫米波开关器件测试、建模技术及其应用。采用0.15μm GaAs PHEMT工艺成功制作了一款Ka波段5位数控移相器MMIC,对毫米波数控移相器MMIC集成电路的设计、制作过程进行了阐述,并给出了测试结果。电路设计采用了开关滤波拓扑结构,运用微波探针在片测试系统对芯片进行了实测,在34~36 GHz范围内获得了优异的电性能。给出了移相器的测试曲线,32态均方根移相误差(RMS)5°,插入损耗典型值8 dB,输入/输出电压驻波比系数典型值2,芯片尺寸为2.5 mm×1.5 mm×0.1 mm。     

0.13-μm CMOS Phase Shifters for X-, Ku-, and K-Band Phased Arrays

Two 4-bit active phase shifters integrated with all digital control circuitry in 0.13-mum RF CMOS technology are developed for X- and Ku-band (8-18 GHz) and K-band (18-26 GHz) phased arrays, respectively. The active digital phase shifters synthesize the required phase using a phase interpolation process by adding quadrature-phased input signals. The designs are based on a resonance-based quadrature all-pass filter for quadrature signaling with minimum loss and wide operation bandwidth. Both phase shifters can change phases with less than about 2 dB of RMS amplitude imbalance for all phase states through an associated DAC control. For the X- and Ku-band phase shifter, the RMS phase error is less than 10^o over the entire 5-18 GHz range. The average insertion loss ranges from to at 5-20 GHz. The input for all 4-bit phase states is typically at -5.4 plusmn1.3 GHz in the X- and Ku-band phase shifter. The K-band phase shifter exhibits 6.5-13 of RMS phase error at 15-26 GHz. The average insertion loss is from 4.6 to at 15-26 GHz. The input of the K-band phase shifter is at 24 GHz. For both phase shifters, the core size excluding all the pads and the output 50 Omega matching circuits, inserted for measurement purpose only, is very small, 0.33times0.43 mm² . The total current consumption is 5.8 mA in the X- and Ku-band phase shifter and 7.8 mA in the K-band phase shifter, from a 1.5 V supply voltage.     

A four-input beam-forming downconverter for adaptive antennas

A four-input beam-forming downconverter for adaptive antennas is described. It consists of 2-bit variable gain amplifiers (VGAs), 5-bit local oscillator (LO) signal phase shifters using double RC-bridge circuits, and mixers. The VGAs adjust gain deviation between signal paths. A differential-signal-to-eight-phase-signal converter is employed as a part of the LO phase shifter to reduce the chip size. A maximum phase error of 4.1/spl deg/, which is less than 1/2 LSB, is achieved. This error value indicates that the required phase shifter accuracy and the necessary isolation between the VGAs has been achieved. This beam-forming IC is applicable to receivers with adaptive antennas, and is expected to help to reduce the costs of adaptive antenna systems.     

An MMIC active phase shifter using a variable resonant circuit [andMESFETs]

This paper describes a monolithic-microwave integrated-circuit (MMIC) active phase shifter using a variable resonant circuit with a large amount of variable phase. We first propose a novel active phase-shifter configuration that uses a variable resonant circuit with second-order all-pass network characteristics. Phase can be changed with a constant amplitude by varying the capacitance or the inductance of the resonant circuit. Next, an experimental MMIC active phase shifter with input active matching is presented. A phase shift of over 100° and an insertion loss of 4±1 dB are obtained from 2.2 to 2.8 GHz. The chip size is less than 1.0 mm². Finally, an experimental 360° MMIC active phase shifter is presented. Over the bandwidth of 40 MHz at 2.44 GHz, the insertion gain is 2.0±0.7 dB and the phase error is within ±4° when measured in 30° steps     

Compact reflective microstrip phase shifter for traveling wave antenna applications

A varactor diode based microstrip phase shifter for 5.8GHz is presented. It is designed for use in microstrip traveling wave antennas where there is a strict limitation on the available space for the phase shifters. To meet all requirements, a reflective type phase shifter is chosen. Such a phase shifter includes a hybrid coupler. A compact branch line coupler is designed to make the phase shifter fit between the radiating elements in the antenna, while maintaining sufficient electrical performance. Phase shifters are designed with different types of stubs connecting the diodes to ground. A phase tuning range of 62/spl deg/ is measured for a phase shifter with parallel open stubs, and 92/spl deg/ with shorted stubs. Insertion loss is in both cases less than 0.6dB. A complete five-element array antenna is built and characterized. Measurements show beam scanning angles within /spl plusmn/32/spl deg/ from broadside.     

A novel monolithic HBT-p-i-n-HEMT integrated circuit with HBTactive feedback and p-i-n diode variable gain control

We report the world's first functional MMIC circuit integrating HBT's, HEMT's, and vertical p-i-n diodes on a single III-V substrate. The 1-10 GHz variable gain amplifier monolithically integrates HEMT, HBT, and vertical p-i-n diode devices has been fabricated using selective MBE and a merged processing technology. The VGA offers low-noise figure, wideband gain performance, and good gain flatness over a wide gain control range. A noise figure below 4 dB was achieved using a HEMT transistor for the amplifier stage and a wide bandwidth of 10 GHz. A nominal gain of 10 dB was achieved by incorporating HBT active feedback techniques and 12 dB of gain control range was obtained using a vertical p-i-n diode as a varistor, all integrated into a compact 1.5×0.76 mm² MMIC. The capability of monolithically integrating HBT's, HEMT's, and p-i-n's in a merged process will stimulate the development of new monolithic circuit techniques for achieving optimal performance as well as provide a foundation for high performance mixed-mode multifunctional MMIC chips     

Wide-band RF photonic second order vector sum phase-shifter

A novel technique to extend the phasing range of the vector sum phase shifter by exploiting its second order response is proposed and implemented. A continuously variable phase shift is demonstrated between 8 and 16 GHz with phasing range exceeding 450/spl deg/ measured at 16 GHz. Good agreement between the predictions and measurements has been obtained.     

A monolithically integrated HEMT-HBT low noise high linearityvariable gain amplifier

We report on a 1-6 GHz HEMT-HBT three-stage variable gain amplifier (VGA), which is realized using selective molecular beam epitaxy (MBE). The VGA integrates an HEMT low noise amplifier with an HBT analog current-steer variable gain cell and output driver stage to achieve a combination of low noise figure, wide gain control, and high linearity. The HEMT-HBT VGA MMIC obtains a maximum gain of 21 dB with a gain control range >30 dB, a minimum noise figure of 4.3 dB, and an input IP3 (IIP3) greater than -4 dBm over 25 dB of gain central range. By integrating an HEMT instead of on HBT preamplifier stage, the VGA noise figure is improved by as much as 2 dB compared to an all-HBT single-technology design. The HEMT-HBT MMIC demonstrates the functional utility and RF performance advantage of monolithically integrating both HEMT and HBT devices on a single substrate     

A 1-GHz active phase shifter with a ferroelectric varactor

An active phase shifter circuit implemented with discrete components is reported. The tuning element, a ferroelectric varactor, is a parallel plate capacitor with Ba/sub 0.5/Sr/sub 0.5/TiO/sub 3/ (BST) as the dielectric. The circuit consists of two bipolar junction transistors coupled with a feedback network, which contains the varactor and thus produces a transfer function that can be varied with a control voltage. The active nature of the circuit allows for signal gain, while the BST varactor provides a high-Q tuning element. This represents an improvement over strictly passive phase shifters with ferroelectric elements. Circuit simulation results are presented and compared with measured data from the implemented system. The network, even with markedly nonideal transistors, can provide a true all-pass response over the frequency band of interest (200-1100 MHz). The measurement results demonstrate an analog tunability of about 100/spl deg/ with a gain variation of about 0.6 dB at I GHz when using a BST capacitor with a tunability of 2.75:1.     

Noise analysis of a photoreceiver using a P-I-N and GaAs HBT distributed amplifier combination

A noise analysis for a common-collector-cascode traveling wave HBT preamplifier is developed. The photoreceiver, consisting of a P-I-N and GaAs HBT MMIC distributed amplifier, was implemented using Nortel's f/sub T/=70 GHz GaAs HBT process, is the first to have a P-I-N mounted on the MMIC chip. The P-I-N preamplifier, having a measured bandwidth of 22 GHz, displayed a measured average equivalent input noise current density of 24 pA//spl radic/Hz. Good agreement was obtained between the predicted and measured noise performance.     

Printed and Integrated CMOS Positive/Negative Refractive-Index Phase Shifters Using Tunable Active Inductors

This paper presents a printed and an integrated bi-directional tunable positive/negative refractive-index phase shifter utilizing CMOS tunable active inductors (TAIs). The printed phase shifter is comprised of a microstrip transmission line (TL), loaded with series varactors and a shunt monolithic microwave integrated circuit (MMIC) synthesizing the TAI. Using the TAI extends the phase tuning range and results in a low return loss across the entire tuning range. The integrated circuit (IC) phase shifter replaces the TLs with suitable lumped L-C sections. This enables integrating the entire phase shifter on a single MMIC, resulting in a compact implementation. The TAI used for both phase shifters is based on a modified gyrator-C architecture, employing a variable resistance to independently control the inductance and quality factor. The TAI is fabricated in the 0.13-mum CMOS process and operates from a 1.5-V supply. The TAI chip is used to implement the TL phase shifter, which achieves a phase of -40deg to +34deg at 2.5 GHz with less than -19-dB return loss from a single stage occupying 10.8 mm times 10.4 mm. The IC phase shifter is fabricated in the same process and achieves a phase from -35deg to +59deg at 2.6 GHz with less than -19-dB return loss from a single stage occupying 550 mum times 1300 mum.