A Five-Port Matched Pseudo-Magic Tee

The five-port matched pseudo-magic tee consists of an input waveguide, two load arm waveguides which are coupled into the input waveguide with +90° and -90° phase shifts, respectively, and an output waveguide which is split into two load waveguides by a septum. The improvements include a much broader matching and isolation bandwidth, higher isolation between arms, better matching into arms, and a variety of modifications for different applications. These characteristics have been obtained by employing frequency-insensitive phase shifters. Hence, frequency coverage is mainly limited by mechanical asymmetry and the characteristics of the directional coupler in the magic tee. While this type of hybrid junction is not a true magic tee because the load arms are not used as the input arm, it does have several applications which an ordinary magic tee does not have. X-, K-, and M-band models were examined experimentally, and highly sensitive and accurate impedance measurements were made.     

A new peak detector based on usage of second-generation current conveyors

A new precision peak detector (full-wave rectifier) of input sinusoidal signals, which employs four two second-generation current conveyors and five metal-oxide-semiconductor transistors, is presented in this paper. The circuit gives a dc output voltage that is the peak input voltage over a wide frequency range, with a very low ripple voltage and low harmonic distortion. The proposed circuits use an all-pass filter as a 90° phase shifter of the processed input signal. The results of the calculations are verified using SPICE simulations.     

Double Dielectric-Slab-Filled Waveguide Phase Shifter

A field theory method based on the orthogonal expansion into eigenmodes is presented for the design of double dielectric-slab-filled waveguide phase shifters with linearly tapered sections. Prototypes of 90° differential phase shift with reference to a corresponding empty waveguide of the same length achieved typically about +-4° phase error and less than -30-dB input reflection within +-5-percent bandwidth, for WR 102-band (7-11 GHz) through WR 28-band (26.5-40 GHz) waveguides. Design curves for differential phase shifts of 12.25°, 22.5°, 45°, 90°, 180°, and 270° are given. Utilizing the differential phase compensation effect of the dispersive behavior of the dielectric-filled and empty reference waveguides, the phase error is only +-1° within +-8.5-percent bandwidth. Further investigations include composite phase shifters, mechanical lateral displacement, and tolerance influences. An experimental 90° phase shifter for 14-GHz midband frequency shows good agreement between theory and measurements.     

Field Theory Design of Ferrite-Loaded Waveguide Nonreciprocal Phase Shifters with Multisection Ferrite Or Dielectric Slab Impedance Transformers

Impedance-matched ferrite-loaded waveguide nonreciprocal phase shifters are designed using the method of field expansion into eigenmodes, which includes higher order mode interaction between the step discontinuities. Computer-optimized Ku -band ferrite stepped design examples, of 45° and 90° nonreciprocal differential phase shifts, attain typically about 2° phase error and less than -25 dB input reflection within a bandwidth of about 5 percent. Compact designs are achieved by thicker uniform ferrite slabs with dielectric transformer sections at each end. The theory is verified by comparison with available results from measurements and other methods.     

Design of novel wideband reflective phase shifters with wide range of phase applications

This paper presents wideband compact differential reflective phase shifter based on the double layer slot-coupled coupler configuration. This novel phase shifter arrangement consists of a 3-dB hybrid coupler with the coupled and transmission ports terminated with rectangular and elliptically shaped microstrip loads. By altering the ports termination of the coupler, phase shifters propose differential phase ranging from −90° to +90° over 1.3–5.9G Hz frequency band. To achieve different range of phase performance, the proper reactance is calculated at the outputs of coupler. These reactances are transformed to the elliptical or rectangular-shaped microstrip load with various dimensions for every phase shifter. The calculation and simulations results show that the developed circuits could provide ±30°, ±60°, ±45° and ±90° differential phase shifts. For verification of this wideband phase shifter design method, two phase shifter example with rectangular and elliptical load termination is fabricated and measured. The measured return loss of the phase shifter with elliptically load is better than 10 dB over 1.3–5.9G Hz frequency band as well as insertion loss is less than 1 dB. The phase shift deviation is less than 2.1°. The results demonstrate that the proposed phase shifters are well suited for use in GPS/LTE/WiMax/WLAN frequency bands.     

An X-band 22.5°/45° digital phase shifter based on switched filter networks

The design approach and performance of a 22.5°/45°digital phase shifter based on a switched filter network for X-band phased arrays are described. Both the MMIC phase shifters are fabricated employing a 0.25μm gate GaAs pHEMT process and share in the same chip size of 0.82×1.06 mm². The measurement results of the proposed phase shifters over the whole operating frequency range show that the phase shift error is less than 22.5°±2.5°, 45°±3.5°, which shows an excellent agreement with the simulated performance, the insertion loss is within the range of 0.9-1.2 dB for the 22.5°phase shifter and 0.9-1.4 dB for the 45°phase shifter, and the input/output return loss is better than -12.5 and -11 dB respectively. They also achieve the similar P_1dB continuous wave power handing capability of 24.8 dBm at 10 GHz. The phase shifters show a good phase shift error, insertion loss and return loss in the X-band (40%), which can be employed into the wide bandwidth multi-bit digital phase shifter.     

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.     

On the correlation between wide-band arrays and array simulators

A ninety-six element scanning array, which operates over an octave bandwidth, has been built and tested. The array beam is steered with digital latching ferrite phase shifters, which have low insertion loss and essentially constant phase shift over considerably more than an octave. A reasonable match has been achieved through the use of dielectric transformers at both the input and radiating apertures. The array performs properly over nearly an octave bandwidth for scan angles up to 60°, but at the upper end of the frequency band, the thick dielectric transformers caused a surface wave-type phenomenon and a subsequent loss of the main beam. An examination of the occurrence of `lost beams' at scan angles of 60° showed that these effects could be predicted from simulator measurements performed at higher frequencies and smaller scan angles     

A new tunable current-mode peak detector

The paper presents a completely new realization of peak detector/full-wave rectifier of input sinusoidal signals employing four CCCIIs (controlled current conveyors), metal-oxide–semiconductor transistors and a single grounded capacitor, without any external resistors and components matching the requirements. The circuit gives a DC output voltage that is the peak input voltage over a wide frequency range, with a very low ripple voltage and low harmonic distortion. The proposed circuit uses an all-pass filter as a 90° phase shifter of the square value of the processed input signal. The proposed circuit is very appropriate to be further developed into integrated circuits. To verify the theoretical analysis, the circuit HSPICE simulations were also included, showing good agreement with the theory.     

GaAs active structures with applications to microwave wideband 90° phase shifters and bandstop filters

Lumped-element second-order active filters are presented which can either be tuned to an all-pass response and then especially used in 90° phase shifters, or tuned to a bandstop response. Their structures have been chosen so that they can be easily implemented in the microwave domain. Preliminary simulations have shown that the filter having the highest-frequency capabilities results in a 90^° phase shifter operating up to the (6 GHz, 1O GHz) band, and that its centre frequency can be tuned up to 15 GHz when it is used as a bandstop filter.     

Performance improvement of RoF transmission link by using 120° hybrid coupler in OSSB generation

This paper presents an analysis, simulation and comparison of the performance of Optical single sideband radio over fiber system based on a dual drive Mach Zehender modulator using 90° and 120° hybrid coupler including the effects of phase noise from RF signal oscillator and laser source, fiber dispersion. Signal to noise ratio (SNR) is significantly influenced by phase noise from RF signal oscillator. On comparison with conventional 90° hybrid coupler system, the performance of the considered system improves by 0.78 dB in terms of SNR, when RF and laser phase noises are increased.     

X波段4bit MMIC数字移相器的设计与实现

基于WIN 0.25 μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,设计并制备了一款X波段4 bit单片微波集成电路(MMIC)数字移相器.22.5°和45°移相单元采用开关滤波型拓扑结构,90°和180°移相单元采用高低通滤波型拓扑结构.对拓扑结构工作原理进行分析,并采用ADS2014软件完成电路的电磁仿真及优化.测试结果表明,该4 bit MMIC数字移相器获得了优良的宽带性能,且与仿真结果吻合良好.在8～ 13 GHz频带内,移相器的均方根(RMS)相位精度误差小于6.5°,插入损耗优于-6.8 dB,RMS插入损耗波动低于0.5 dB,输入回波损耗优于-13 dB,输出回波损耗优于-9.5 dB.该4 bit MMIC数字移相器在相对带宽为47％的X频段内性能优良,适用于有源相控阵雷达等通信系统中.     

Simple phase meter with lead/lag indication

A simple and inexpensive circuit for measuring the phase angle difference between two waves with lead/lag indication is described. The proposed circuit may be adopted in the laboratory as an attachment to a commercially available analogue/ digital multimeter to measure the phase difference. The response is linear over a range 0 to + 180^° and is unaffected by the input frequencies in the range 6 Hz–1.2 kHz. For distorted waveforms, the paper also gives a simple scheme to measure the displacement angle which in turn suggests its use in a high-power-factor self-compensated alternating voltage controller.     

An A/D Converter with 10 Bits/Sample by 20 MHz Sampling Rate

An A/D converter circuit system with a very high bit-rate has been developed. It is a series-parallel type, and the input of the last A/D stage is equivalently ac-coupled. This can be allowed by the statistical charactertstics of input signals. A prototype of this A/D converter has the following characteristics: 1) dc coupled analog input-able to accept almost all analog signals as well as television signals; 2) sampling frequency up to 20 MHz; 3) linear coding scheme with 10 bits per sample; 4) linearity error of less than one third of quantizing level; 5) differential gain and differential phase of 0.4% and 0.25°, respectively; and 6) operating temperature range of from 0° to 50°C.     

Phase Shifts in Single- and Dual-Gate GaAs MESFET's for 2-4-GHz Quadrature Phase Shifters

The variation of transmission phase for single- and dual-gate GaAs MESFET's with bias change and its probable effects on the performance of an active phase shifter have been studied for the frequency range 2 to 4 GHz. from measured S-parameter values for single- and dual-gate transistors, the element values of the equivalent circuits were fitted by using the computer-aided design program SUPER COMPACT. For the normal full-gate voltage range 0 to -2 V at V/sub DS/= 4 V, the single-gate MESFET varies in transmission phase from 142° to 149° at 2 GHz, and from 109° to 119° at 4 GHz. However, with drain voltage varied from 0.3 to 4 V and a constant gate-voltage bias of 0 V, the phase shifts are much larger, 105° to 145° at 2 GHz and 78° to 112° at 4 GHz. this suggests that large phase shifts may be expected in a dual-gate device and this is found to be so. With V/sub DS/= 4 Vand V/sub GS1/= - 1.0 V, variation of control (second) gate bias from 0 to - 1.75 V for the NE463 GaAs MESFET produces a transmission phase variation from 95° to 132° at 2 GHz and 41° to 88° at 4 GHz. Such phase shifts cause both amplitude and phase errors in phase-shifter circuits of the kind where signals from two FET channels are combined in quadrature with their gate voltages controlled to provide 0° to 90° phase control with constant amplitude. For the single-gate FET examined, the expected amplitude and phase errors are 0.30 dB and 6° at 2 GHz, and 0.36 dB and 10° at 4 GHz. If dual-gate FET's are used in similar circuits, the distribution of errors is different. For NE463 devices, the corresponding figures are 0.56 dB and 2° at 2 GHz and 1.2 dB and 3° at 4 GHz. the advantage of the dual-gate configuration is that the input impedance conditions are more constant than for the single-gate configuration.     

A New Approach to the Design of a Phase Modulator with Low Nonlinear Distortion

Phase modulation can most directly be effected by a device whose output is a sinusoidal function of its input. In this paper a phase modulator is described in which a linear segmental approximation of the sinusoidal function is used. Performance results in terms of a phase difference from perfect linearity (Delta Phi) and signal-to-distortion ratio (SDR) are given. For eight-segment approximationDelta Phiis 0.06° and SDR is 62.3 dB in the rangepm90deg.     

一种新颖的DC～50GHz低插入相移MMIC可变衰减器

介绍了一种新颖的 DC～ 5 0 GHz低相移、多功能的 Ga As MMIC可变衰减器的设计与制作 ,获得了优异的电性能。微波探针在片测试结果为 :在 DC～ 5 0 GHz频带内 ,最小衰减≤ 3 .8d B,最大衰减≥ 3 5± 5 d B,最小衰减时输入 /输出驻波≤ 1 .5 ,最大衰减时输入 /输出驻波≤ 2 .2 ,衰减相移比≤ 1 .2°/d B。芯片尺寸 2 .3 3 mm× 0 .68mm× 0 .1 mm。芯片成品率高达 80 %以上 ,工作环境温度达 1 2 5°C,可靠性高 ,稳定性好     

A Fast-Switching Low-Loss 12-GHz Microstrip 4-PSK Path Length Modulator

A 4-PSK microstrip modulator operating at data rates of up to 800 Mbits/s at 12 GHz is described. The circuit is made of two cells in series. Each cell consists of a 3-dB branch-line hybrid coupler and two BTL p-i-n diodes. One cell provides 0° or 90° phase shifts, and the Other 0° or 180° phase shifts, so that four carrier phase values are obtained by appropriately exciting the two cells. The switching time of each cell is 200 ps. Simultaneous switching of both cells increases the switching time to a maximum value of 400 ps. The phase waveforms are nearly rectangular at the above-mentioned data rates. RF insertion loss is 1 dB ± 0.1dB for the four phase values over the 11.7-12.2 GHz frequency band.     

90 degree phase matched generation of 266 nm light in 90 percent deuterated KD*P

Experiments have been performed to determine the temperature necessary to achieve 90° phase matched generation of the fourth harmonic of a Nd:YAG laser in 90 percent deuterated KD*P. A phase matching temperature of 62°C was found.     

Design of digital loaded-line phase-shift networks for microwave thin-film applications

This paper decribes the design approach, fabrication techniques, and electrical performance for two types of microwave hybrid thin-film phase shifters. Emphasis is placed on the practical aspects of the overall design and fabrication. A simplified set of design equations for loaded-line phase-shift networks is presented and divided into three categories based on the type of loading employed. The two circuits presented are a 4-bit 90° network employing single-section multibits to minimize physical size, and a 4-bit 360° network employing the 45° section as a basic building block.