Synthesis of phase shifters based on a single stepped transmission line with a stub

A two-criteria problem of the synthesis of differential phase shifters designed on the basis of a new structure-a symmetric stepped transmission line with a stub connected in the middle of the structure—is solved. Optimum parameters of such phase shifters are calculated for phase shifts φ₀ = 11.25°−135° and bandwidths of 40% and 67%. It is found that the wave impedances of the steps monotonically decrease from feeding lines to the structure center and optimum wave impedances of the stub and sections decrease with increasing φ₀. It is shown that structures with different stubs are analytically equivalent. Parameter values of the phase shifter are improved as compared to the parameter values of a known design. A 90° microstrip phase shifter is experimentally studied in a frequency band of 2–4 GHz. It is found that the maximum discrepancy between the theoretical and experimental characteristics is 5° and the maximum value of the standing-wave ratio is 1.11     

A New 90° Constant Phase Shifter for the VHF Band

This concise paper presents the realization of a 90°constant phase shifter in the VHF band, which is entirely different from the conventional method for the realization of constant phase shifters in the audio frequency range. The construction of the 90° constant phase shifter is simple and can be easily realized by using a transmission line, and the lumped constant elements, R, L, C. Experimental verification is included.     

Analysis of bilateral finline couplers

Although characteristics of bilateral finline as a transmission line have been studied in detail, the behaviour of this structure as a coupler has not received much attention so far. The letter represents a study of phase constants and characteristic impedances of the even and odd modes of bilateral finlines as couplers, leading to the exposition of some useful design information.     

High sensitivity nanostructure incorporated interdigital silicon based capacitive accelerometer

Interdigital structures are realized on silicon substrates with high sensitivity to acceleration. The process employs a combination of anisotropic back-side micromachining with front-side vertical deep reactive ion etching of silicon. The incorporation of silicon-based nano-structures on the vertical planes of fingers leads to a significant increase in the capacitance of the device from 0.45 for simple planes to 40 pF for the nano-structured planes. Such structures show high sensitivity to inclination and accelerations, which could be due to field emission of electrons from nano-metric features. Around 8% change in the capacitance is observed upon a tilting sensor from 0° to 90° angle, which makes it proper for possible use as an earthquake sensor. A preliminary model for the capacitance and its dependence on the measurement voltage is presented.     

基于开口谐振环的毫米波差分移相器设计

该文提出了一种工作于30～32 GHz的毫米波差分移相器,其尺寸为30 mm×18 mm×0.127 mm。该移相器以微带线为基础进行设计,由中心圆环及一对开口谐振环(SRR)共同组成。通过改变中心圆环的半径大小实现在工作频段内的S参数优化。以参考线的输出相位为基准,通过改变开口谐振环半径依次实现22.5°、45°、90°的差分移相。结果表明,在所设计的频段内,该移相器的回波损耗小于-10 dB,插入损耗小于1.4 dB,仿真最大移相误差小于5°。该移相器结构简单,便于制造。通过实物样品测试,验证了其仿真结果的可靠性。     

A Low-Loss Ku-Band Monolithic Analog Phase Shifter

A GaAs monolithic Ku-band analog phase shifter integrating 90° branch line coupler with planar varactor diodes has been fabricated for the first time. A phase shift of 109° +- 3° with an insertion loss of 1.8+-0.3 dB was measured from 16 to 18 GHz. A 360° phase shifter with 4.2+-0.9 dB insertion loss was realized in the same frequency range by connecting three phase-shifter chips in series. To our knowledge, this is the lowest insertion loss obtained by a 360° Ku-band phase shifter using monolithic circuits. In addition, hyperabrupt varactors using nonuniform doping profiles increased the phase shift by more than 30° and produced a more linear dependence of phase shift on control voltage.     

A simple quadrature oscillator for generating triangular waves and square waves

A new method for the relatively cheap generation of triangular waves and square waves is described. The present instrument is versatile in generating pairs of waves: two waves for each one of the waveforms. Each one of the waves is 90° out of phase with respect to the other wave of the same form. This quadrature operation is similar to that of common sinewave oscillators, but it is not usually known for the generation of square waves and triangular waves. The new system has been realized successfully and electronically by employing only one integrated circuit.     

Intermodulation properties of double- and triple-circuit parametric amplifiers with nonlinear barrier capacitance

There have been performed an experimental investigation of intermodulation effects in narrowband regenerative double- and triple-circuit parametric amplifiers (RDPA and RTPA) with nonlinear barrier capacitance. It has been obtained that their single-signal and double-signal intermodulation characteristics are of the conventional form, and their phase shifts in the vicinity of the resonance frequency are close to 90°, that is not enough for the compensation of nonlinear distortions in the case of amplifiers cascading. It has been demonstrated that the introduction of the additional oscillatory circuit at the double signal frequency into RDPA does allow effective compensation of the intermodulation interferences of odd order in the single-stage parametric amplifier.     

星地激光通信中光学数字相干接收机的研究

光学数字相干接收技术在星地激光通信中具有广泛的应用前景。本文以窄线宽DFB激光器作为光源,采用自动频率控制环路,结合光学混频和数字信号处理技术,实现了最高速率为1.25 Gbps的相干光通信。实验结果表明,自动频率控制环路能够将信号光和本振光之间的频率差实时控制在10 Hz以内,光学混频器输出的I、Q两路信号相位差能够长时间稳定保持90°,基于FPGA的载波相位补偿技术能够有效修正自动频率控制环路的相位残差,在误码率为10-6条件下,该接收机的灵敏度优于每比特54个光子。     

Planar Broad-Band 180° Hybrid Power Divider/Combiner Circuit

A planar broad-band 180° hybrid is presented. The hybrid is realized using a 3-dB 90° hybrid and a 0-dB 90° tandem hybrid. An interdigitated version of the hybrid fabricated on alumina substrate performed well over the 4-8-GHz band. The hybrid has an insertion loss of 0.5 dB, phase imbalance of +-7°, and an isolation of better than 18 dB over the band.     

Accurate Analysis of Coupled Strip-Finline Structure for Phase Constant, Characteristic Impedance, Dielectric and Conductor Losses

Propagation constant, characteristic impedance, dielectric loss, and conductor loss of coupled strip-unilateral finline is here computed for the first time. The technique of analysis is based on the assumption of hybrid wave propagation implemented through the spectral domain approach for the phase constant. A perturbation method together with the spectral analysis has been applied to find the losses. The basis functions used to approximate fields within unilateral finline gap and currents on the strip have been selected as Legendre polynomials for the unbounded field or current and trigonometric functions for bounded field or current. The Green's function matrix in the spectral domain for the two distinct planes of the coupled strip-unilateral finline has also been presented. This gives the opportunity for direct implementation in the analysis of other similar structures. The possibility of the extension of the technique to shielded stratified dielectric with distributed planar conductor within different layers has been also discussed.     

A compact millimeter-wave finline and microstrip hybrid integrated front-end

Unlike usual millimeter-wave(MMW) beam lead mixer, an integrated mixer using packaged diodes with large junction area is designed, and a novel dielectric resonator stabilized microstrip oscillator is given. On these bases, a high performance MMW finline and microstrip hybrid integrated front-end has been developed with minimum double side band noise figure of 4 dB and frequency temperature coefficient of 5～10 PPm/°C. It has been fabricated in small amounts and works well in many MMW systems.     

Ka 波段宽带单边带调制器集成电路的设计

基于相移法实现SSB(单边带)调制器理论,设计制造了一种Ka 波段宽带SSB 调制器集成电路。对相移法产生单边带调制信号的原理进行了分析,利用无源电路的3D 电磁仿真分析和ADS 整体电路非线性仿真相结合的方法对调制器进行了优化。设计制造的90°相移电桥网络和同相合成器满足了产生Ka 波段SSB 信号的幅相要求,同时给出了测试结果。调制器在30 ~36GHz 频带内插入损耗臆14dB;载波和对称边带抑制逸15dB;其它边带抑制逸13dB;输入1dB 压缩功率38dBm;外形尺寸18mm×6mm。这种相移法单边带调制器不需要带通滤波器,具有电路简单,载波抑制比高,对相位误差要求不高的优点。     

Monolithic dual-gate GaAs FET digital phase shifter

The design, fabrication, and characterization of a fully monolithic FET digital phase-shifter circuit is described. The circuit is designed around a unique dual-gate FET structure Operating as a switchable single-pole, double-throw amplifier. Each 2.5 × 3.0-mm chip has one bit (e.g., 22.5°, 90°, etc.) of phase control. The circuit, which includes all dc bypass circuitry on-chip, features thin-film lumped element capacitors and inductors, air-bridge crossovers and interconnects, via-hole frontside grounding, and integral beam leads. The fabrication of these elements is described in some detail. The phase-shifter circuit gives a peak gain of 3 dB across a 10-percent bandwidth in X-band. A method of achieving continuous phase and amplitude control using a 90° bit chip is described. Finally, phase performance of a four-bit digital phase shifter realized by cascading four monolithic active phase-shifter chips is reported.     

Design considerations for integrated CMOS reflective-type phase shifters

An analysis of reflective-type phase shifters with transformed single-resonant loads for integrated CMOS phased-array implementations is presented. Several components of the standard lumped-element coupler can be eliminated without significant performance degradation, to allow more compact implementations. It is found that the varactor should be chosen as small as feasible to minimize sensitivity to parasitic resistance. Larger varactors reduce sensitivity to parasitic capacitance, but this can be compensated for in the phase shifter design. A general design procedure for reflective-type phase shifters is given. A phase shifter operating at 2.0 GHz has been designed and implemented in a 0.18 μm CMOS process using the design procedures outlined, and it occupies an area of 0.75 mm² and consumes 6.8 mW of power. The measured phase shift range is 308° for a control voltage varying from 0–1.8 V, which to our knowledge is the largest phase shift range of any CMOS reflective-type phase shifter reported to date.     

11-GHz MIC QPSK Modulator for Regenerative Satellite Repeater

An 11-GHz MIC QPSK modulator for a 14/11-GHz, 120-Mbit/s regenerative satellite repeater is described. The modulator consists of cascaded 90° and 180° phase switches, realized with circulators and PIN diodes. The static and the dynamic behavior are presented. It is shown how the bit-error-rate performance is deteriorated by slow switching transients and timing errors.     

太赫兹超材料分束器设计及其特性分析

提出一种超材料太赫兹分束器,其单元结构由顶层金属条带、中间介质层和底层金属板组成。利用4个旋转步进为45°的单元周期排列构成了4×4的相位梯度超表面。当太赫兹波垂直入射到阵列表面时,电磁波被反射成四束能量相等但传播方向不同的波,且不同频点的反射角不同。该分束器具有体积小、成本低的优点,可应用于太赫兹隐身和太赫兹成像等方面。     

A Monolithic Single-Chip X-Band Four-Bit Phase Shifter

X-band GaAs monolithic passive phase shifter with 22.5°, 45°, 90°, and 180° phase bits are developed using FET switches. By cascading all four bits, a four-bit digital phase shifter with 5.1+-0.6-dB insertion loss is realized on a single 6.4 x 7.9 x 0.1-mm chip.     

Finline L to Q band upconverter

An L to Q band upconverter using finline configuration is developed. The conversion losses of 9.45±0.35 dB are achieved over 400MHz bandwidth. A more effective 180° hybrid and a planar backshort are used in the finline upconverter.     

Monolithic Dual-Gate GaAs FET Digital Phase Shifter

The design, fabrication, and characterization of a fully monolithic FET digital phase-shifter circuit is described. The circuit is designed around a unique dual-gate FET structure operating as a switchable single-pole, double-throw amplifier. Each 2.5 X 3.0-mm chip has one bit (e.g., 22.5°, 90°, etc.) of phase control. The circuit, which includes all dc bypass circuitry on-chip, features thin-film lumped element capacitors and inductors, air-bridge crossovers and interconnects, via-hole frontside grounding, and integral beam leads. The fabrication of these elements is described in some detail. The phase-shifter circuit gives a peak gain of 3 dB across a 10-percent bandwidth in X-band. A method of achieving continuous phase and amplitude control using a 90° bit chip is described. Finally, phase performance of a four-bit digital phase shifter realized by cascading four monolithic active phase-shifter chips is reported.