Broadband microwave photonic phase shifter based on polarisation rotation

A broadband microwave photonic phase shifter is presented based on the polarisation properties of a Mach-Zehnder intensity modulator and nonlinear polarisation rotation in a semiconductor optical amplifier. The system can realise about 150deg phase shift in the frequency range from 50 MHz to 19 GHz.     

新型数控光纤矢量和微波光子移相器

针对相控阵天线中基于光纤的微波光子移相器原理进行研究,并设计了新型方案,通过引入可调分光器和保偏光纤,降低了移相器的复杂性和相干干涉损耗,在对光纤长度的精度要求上有很大改善,从而提高了可实现性,增强了移相器的可控性。研究了分光系数和频率对信号相位和幅度的影响,实现了超过140的相移。最后通过设计数控电压源实现对分路器驱动电压的调整,从而改变两路光纤的光分量,最终实现对输出信号相位的数字控制。该新型微波光子移相器方案易于实现,并具有一定的创新性。     

基于矢量和的微波光子移相器研究

基于矢量和（vectorsum）原理,利用50：50光纤耦合器、可变光延时线（VDL）、可变光衰减器（VOA）构建了微波光子移相器。以宽带光为载波有效地解决了合波处光波相位不同引起的微波信号不稳定的问题;利用马赫-曾德（M—Z）LiNbO3调制器在不同工作电压下的反相调制特性,设定调制器的不同偏置电压,同时配合调节两支...     

High-Tc superconducting microwave phase shifter

The relation between the surface impedance Z_S(=R_S?jX_S) of superconductors and DC current I has been derived to determine the propagation constant of a superconducting microstrip line, and the relation between the phase delay ? of the superconducting microstrip line and DC current I is also presented. On the basis of these analytical results, a microwave phase shifter has been made by using YBCO superconducting thin film. In this paper, we describe the design principle of phase shifter, its fabrication, and present the experimental results. These measured values agree well with the theoretical curves.     

Voltage variable microwave phase shifter

Results are given on the fabrication, test and theory of operation of a voltage-controlled, continuously variable phase shifter designed to operate from DC to 150 GHz. The device was fabricated in a way that makes it compatible with current gallium arsenide monolithic microwave circuit technology.     

L波段五位数字移相器的宽带自动修调

以 L 波段五位数字移相器的宽带自动修调为例 ,介绍了激光自动修调系统的组成和工作过程 ,讨论了移相器的可修调设计和修调算法的设计。激光自动修调技术可用于多种微波电路 ,可以缩短调试时间 ,降低生产成本 ,满足大批量生产的要求。     

A novel wide-band tunable RF phase shifter using a variable opticaldirectional coupler

We present a novel RF phase-shifter design with a usable bandwidth of 80:1. The design is verified through demonstration of a proof of concept device, consisting of a readily available voltage variable optical coupler fabricated from LiNbO₃, combined with an fiber-optic delay line. The design is analyzed theoretically and measurement of the device confirms the predicted range of operation. Methods of extension of this range of operation are discussed     

A photonic technique for microwave frequency measurement

A novel photonic technique for microwave frequency measurement utilizing dispersion in a multichannel chirped fiber Bragg grating is presented. The technique is based on the amplitude comparison of power fading functions generated by double sideband modulated optical carriers propagating through a dispersive medium.     

Explicit microwave rotary phase shifter calibration algorithm

A microwave rotary phase shifter calibration method described previously by P.I. Somlo et al. (ibid., vol.20, no.8, p.532-7, 1972) requires the device under test (DUT) to be connected in tandem with a two-state phase stepper (flap) of initially unknown phase shift F to form an arm of a phase bridge circuit. The measurement is carried out by setting the DUT sequentially to a series of cardinal points, α_oi, i=1, . . ., M, equally spaced around the dial. At each, the phase bridge is balanced, and after introducing the flap, the new setting α_fi of the DUT needed to return the phase bridge to balance is found. The advantages of the method are that no standard phase shifter is required, that since the method is not a buildup method, errors are not cumulative, and that the phase bridge need not have any long-term stability. The algorithms previously described for data reduction are both iterative. Here, an algorithm that provides an explicit solution for the M unknowns is presented     

布里渊光子晶体光纤环形移频器

通过实验研究了一种光子晶体光纤环形移频器,该移频器基于布里渊频移原理,利用光子晶体光纤布里渊增益高、阈值低的特点,同时利用光纤环形腔选频放大技术获得窄线宽高增益激光输出。实验结果表明:在波长为1 548 nm单纵模光纤激光泵浦下,10 m长光子晶体光纤的受激布里渊散射阈值功率约为457mW,环形腔输出的受激布里渊散射Stokes光相对于入射光移频量为9.778GHz、线宽500 kHz,并且移频量可以通过温度进行微调。该移频器可以用于分布式光纤布里渊传感器和微波发生器。     

Photonic RF phase shifter and tunable photonic RF notch filter

A new photonic RF phase shifter structure for phased array antennas is presented. It is based on a single dual-output modulator and two optical switches and optical attenuators. This can realize continuous phase shifting of 0/spl deg/-360/spl deg/ without altering the signal amplitude. It has the advantages of wide bandwidth, fast response time, and fine tuning resolution. Experimental results demonstrate phase shifts over a 360/spl deg/ phase range, with RF signal power changes of less than 0.2 dB, which is in close agreement with predictions. A tunable photonic RF notch filter, which is based on the new phase shifter, is also presented. Experimental results demonstrate continuous tuning of the photonic notch filter over a wide tuning range, which covers the full free spectral range, which is in good agreement with predictions.     

微波MEMS移相器的特性分析与实现

从移相器的基本原理出发,分别介绍了开关线型、耦合器型和加载线型三种采用微机械加工技术制备而成的微波MEMS移相器的结构特点和工作原理。在此基础上,设计制备了CPW分布式加载线型MEMS移相器,并进行测试和分析,结果表明MEMS移相器较传统的移相器有微型化、低损耗、低成本、宽带等突出优点。     

A novel tunable optoelectronic oscillator based on a photonic RF phase shifter

A novel tunable optoelectronic oscillator （OEO） based on a photonic radio frequency （RF） phase shifter is proposed and analyzed, which consists of a dual-drive Mach-Zehnder modulator （DMZM）, a 90° hybrid coupler and a tunable microwave amplifier （TMA）. This tunable OEO has a simple configuration, and the frequency of the oscillating signal can be tuned by adjusting the amplification factor of the tunable amplifier. The simulation results show that the maxi- mum frequency shift from the center oscillation frequency is 1.48 MHz when the amplification factor of the TMA is set at 10.     

RF and microwave phase shifter using complementary bias techniques

A novel method for the design of an RF phase shifter using a standard foundry process is described. This phase shift achieves very low and near-constant insertion loss. The proposed method uses `complementary' control techniques to keep variable parasitic resistance in a standard transistor to a minimum. Using an only single stage reflection configuration which employs N varactor diodes as a reflection terminator and M varactor diodes, a minimum insertion loss variation can be obtained. The technique is verified by measurement when N=M=1     

InGaAs microwave switch transistors for phase shifter circuits

A new InGaAs insulated-gate FET (IGFET) with 1 μm gate length and three different gate widths has been designed, fabricated and characterized as switch devices for microwave control applications in phase shifter circuits. The devices employed a plasma deposited silicon dioxide gate insulator and had multiple air bridged source regions. The details of the DC current-voltage (I-V) characteristics and small signal S-parameter measurements up to 20 GHz are presented. The switch IGFET's had a drain saturation current density of 300 mA/mm gate width with breakdown voltages of higher than 35 V. An insertion loss of 1.0, 0.6, and 0.4 dB at 10 GHz and 1.4, 0.8, and 0.4 dB at 20 GHz have been measured for the 300, 600, and 1200 μm gate width IGFET's, respectively. Equivalent circuit models fitted to the measured S-parameters for IGFET's yielded on-state resistances from 10.7 to 3.3 Ω, off-state resistances from 734.4 to 186.8 R and off-state capacitances from 0.084 to 0.3 pF as the gate width is increased from 300 to 1200 μm The simulation results using IGFET models for the phase shifter circuits indicated a maximum phase error of 0.11°, 0.26°, and 0.479 with 0.74, 0.96, and 1.49 dB maximum insertion loss and greater than 33, 26, and 19 dB return loss for the 11.25°, 22.5°, and 45° phase bits, respectively, over the 9.5-10.5 GHz frequency band     

Tunable liquid crystal phase shifter for microwave frequencies

A tunable phase shifter using liquid crystal (LC) is presented. The device is fabricated in a fashion similar to LC displays which makes fabrication very simple compared, for example, to MEMS approaches. At the targeted operation frequency of 20 GHz the device offers a performance of above 60 differential phase shift per dB insertion loss and a minimum tuning speed of 340 ms.     

一种中频相同的微波光子信道化接收机

提出一种基于相干光处理的微波信道化接收机,采 用 自由谱范围(FSR)不同的两套光频率梳(OFC,optical frequen cy combs)分别作为 光载波和光本振,使得各个信道的输出具有相同的中频。本文方法将微波信号调制到载波 OFC的每一个 频率分量上,并用法布里-珀罗(F-P)光滤波器对多个信道的调制光边带同时进行带通滤 波,然后与 本振OFC进行相干探测实现频率下转换。若载波OFC比本振OFC的FSR大于1个 信道带宽,并使 F-P滤波器的FSR与本振OFC相等,可得 到等带宽、等中频的微波信道,降低了后续电路的复杂度。对 两个相邻信道进行了实验,将9.74～9.86GHz和9.86～9.98GHz波段的信号分别下转换到两个带宽为120MHz 的中频信道,两个中频信道的中心频率仅相差4MHz分别为900MHz和 896MHz,表明本文方法能够实现等中频的信道输出。     

A wide-band microwave light modulator

An experimental potassium dihydrogen phosphate (KDP) light modulator with a 10 percent (half-m) bandwidth at 6 GHz is described. When arranged for amplitude modulation, a modulation depth of 40 percent was obtained with 10 watts of input power at band center. With a different optical arrangement, phase modulation is also possible. The modulator uses a ring-plane traveling-wave circuit with cylindrical KDP crystals filling the space inside the rings. The crystals are used in the longitudinal mode, i.e., with the light beam along the optic axis, thus avoiding some of the thermal problems associated with transverse node operation. The circuit provides adequate cooling for the crystals and CW or pulsed operation at average RF levels of 10 watts is possible. Measurements indicate that the limitation in bandwidth is due mainly to the dispersion of the circuit and that with suitable modifications bandwidths of 20 percent are quite feasible.     

Electrically tunable microwave phase shifter based on layeredferrite-ferroelectric structure

Based on surface spin wave propagation in a layered structure containing ferrite and ferroelectric materials. Operating characteristics of the phase shifter are investigated theoretically. It is shown that waveguiding elements from planar layered ferrite-ferroelectric structures allow the construction of compact devices with high electrical tunability achieving 10°/V