A novel tunable transmission line and its application to a phase shifter

This letter describes the design of a novel transmission line, where characteristic impedance can be adjusted electronically, and its application to a phase shifter. A tunable transmission line enables microwave circuit designers to have flexibility and better return loss which can enhance its tuning range. A UHF band distributed analog phase shifter, as well as a tunable transmission line, is presented. The characteristic impedance of a fabricated novel transmission line varies from 10 to 69.5/spl Omega/, which demonstrates its tunability, and the fabricated UHF phase shifter using this novel line shows the possibility of better reflection coefficient and wider tuning range over the conventional capacitively-loaded distributed phase shifter.     

Broadband digital phase shifter based on switchable right- and left-handed transmission line sections

A novel approach to design digital phase shifters with the operational bandwidth extended to one octave is presented. An original design of the broadband phase shifter based on switching between transmission lines (TLs) with positive and negative dispersions is considered. An artificial TL with the negative dispersion was implemented as a quasilumped-element coplanar structure using a multilayer technology. The simulated and measured performance of the 180/spl deg/ phase shifter is presented.     

Distributed transmission line phase shifter using parallel-plate ferroelectric thin film varactors

A distributed transmission line phase shifter based on two series connected parallel-plate ferroelectric thin film varactors, which are integrated into single crystal (1 0 0) LaAlO₃ (LAO) wafer, is presented. The equivalent circuit model was simulated by the EM simulation software in an effort to optimize the design. A device with differential phase shifts of 150^o at 8 GHz with a low bias voltage of 12 V was realized.     

Composite right/left handed transmission line phase shifter using ferroelectric varactors

A composite right/left handed (CRLH) transmission line (TL) phase shifter, using ferroelectric (Ba/sub 0.25/Sr/sub 0.75/TiO/sub 3/) varactors as tunable element, is presented for the first time. It is theoretically and experimentally demonstrated how the unique features of CRLH TLs, enables a differential phase shift with flat frequency dependence around the center frequency. The experimental prototype is a coplanar design integrated on a high resistive Si substrate. It includes four CRLH T-unit cells and has a physical length of 3850/spl mu/m. The ferroelectric varactors are realized in parallel plate version. Under 15-V dc bias applied over each varactor, the differential phase shift is flat around 17GHz and has an absolute value of 50/spl deg/.     

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     

Diplexer using composite right-/left-handed transmission line

Any two ports of a lossless reciprocal three-port network can be matched and let another one be mismatched completely. The composite right- /left-handed transmission line (CRLH-TL) has the dual-band property because of its unique hyperbolic-linear dispersion relation. Based on the dual-band property, a novel three-port diplexer is proposed by combining two three-port networks operating at different frequencies. Theoretically, such a three-port diplexer can be designed to operate at two arbitrary frequencies. The simulation results show that the three-port diplexer can separate two different frequencies effectively, and simulation results are found to be consistent with measurement results.     

A tunable all-pass MMIC active phase shifter

This paper describes a novel structure for a monolithic-microwave integrated-circuit active phase shifter based on a bridge all-pass network. The design procedure has been developed, leading to a fixed-frequency circuit with large tunable phase variation, associated to a low-gain ripple, and requiring nearly no design optimization. Simulated results predicted an analog tunable 180/spl deg/ phase variation, at 5-GHz operation frequency. The circuit was implemented using GEC-Marconi pseudomorphic high electron-mobility transistor H40 technology, and measured results validated the proposed design method and circuit structure.     

基于复合左右手传输线相移器的串馈相控阵天线

基于电调复合左右手传输线相移器,提出了一种新型相控阵天线波束控制方式：通过电压控制相移器的相移,从而使相控阵天线中心频率工作在边射方向,并允许向边射外的两个方向进行扫描。作为实例,设计制造了一个应用在ISM波段的平面串联馈电贴片相控阵天线,并对其进行了测试。结果表明：该相控阵天线可实现连续扫描,边射方向波束倾斜小(2°...     

Wide-band balun using composite right/left-handed transmission line

A wide-band balun is developed using a composite right/left-handed (CRLH) transmission line (TL) at 2 GHz. It is composed of a Wilkinson power divider and two phase-adjusting transmission lines, namely the CRLH TL and the conventional TL. The input reflection coefficient is better than -10 dB from 1 to 4 GHz. Over the frequency range of 1.24-3.58 GHz, an amplitude imbalance of less than 0.7 dB and a phase error of less than plusmn10deg have been experimentally demonstrated.     

A phase shifter with one tunable component for a reflectarray antenna

The combination of a dipole and a tunable varactor forms a phase shifter with one tunable component that provides a phase shift over a wide range, from 00 to nearly 3600. The dipole, loaded with a tunable varactor, is used as a patch component of a low-profile reflectarray antenna. An economic assessment shows that the production price of the suggested phase shifter with one tunable component is more than 10 times smaller than the price of the traditional phase shifter, based on p-i-n diode components. The design of such a phase shifter is the goal of this paper. Simulations of the phase shift and loss of the reflected wave as a function of control voltage applied to the varactor were used, based on an analytical model verified by fullwave analysis. The results of simulations are in agreement with measurements. The fast and correct simulation of the reflection coefficient from the dipole loaded with the tunable varactor can be used for the design and optimization of a lowprofile steerable reflectarray antenna.     

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     

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.     

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.     

A new electronically tunable phase shifter employing current-controlled current conveyors

A new canonical current-mode (CM) filter topology is presented. It realizes first-order allpass filtering functions using two dual-output current-controlled current conveyors (DO-CCCII) and a single capacitor. The topology gives both inverting and non-inverting types of these filters. Owing to electronically tunability properties of the CCCII, phase response of the circuit can be controlled by an external control current. Realization of the allpass filter imposes no matching condition. All outputs of the filters exhibit high output impedances so that this property makes the circuits very attractive from the viewpoint of cascading in current mode. The theoretical results are verified with PSPICE simulations using a BJT realization of CCCII.     

Harmonics terminated L-band frequency quadrupler using composite right/ left-handed transmission line

A design method for an L-band frequency quadrupler with composite right/left-handed transmission line is proposed. The left-handed transmission line in the proposed frequency quadrupler suppresses the fundamental component (f0), while the composite right/left-handed λ/4 open stub reduces unwanted higher-order harmonics. From the experimental results, unwanted harmonics are suppressed to achieve harmonic distortion of 51 dBc minimum with output phase noise of -94.34 dBc/Hz at 10 kHz offset.     

基于左手传输线的双线极化微带阵列天线

基于左手传输线,提出了一种新型串联馈电的双线极化微带阵列天线结构.通过上层微带线边馈和下层小孔耦合馈电的方式分别实现了天线单元的垂直极化和水平极化的激励,进而使得该天线单元具有高极化隔离度、低交叉极化和宽频带工作等优点.同时由于左手材料具有相位超前的特性,利用传统的右手微带传输线和左手微带传输线的组合以达到零相位延迟,实现了对上述单元构成的微带阵列天线的串联馈电.相对于传统微带阵列天线,该阵列天线结构简单、面积小、插入损耗小、阵列效率高、易于扩展成更大的平面阵列.     

Dual-mode composite-right/left-handed transmission line ring resonator

The phase response of composite right/left-handed transmission lines is used in the design of a dual-mode ring resonator. The phase can be designed to change the spacing of the resonant modes. Simulation and measured results for a dual-mode ring demonstrate this technique. The designed structure exhibits the elimination of the singlemode resonance at the second harmonic.     

Surface-acoustic-wave phase shifter using electrical depolarisation

An electrically variable phase shifter employing surface acoustic waves is described that uses electrical depolarisation of a poled PZT ceramic. Phase shifting occurs in a depoling region in which an electric field of variable strength opposes the remanent ferroelectric moment, causing a change in the piezoelectric coupling and surface-wave velocity.     

A precise digital phase shifter using a phase-locked loop

A phase-locked loop containing a voltage-controlled oscillator (v.c.o.) synchronised to a harmonic of its fundamental output frequency may be used to form an attractive digital phase shifter providing low phase error with relatively simple circuitry and control requirements. Phase increments of 2?/n radians are obtained, where n is the order of harmonic used.     

A PWM quadrature-booster phase shifter for AC power transmission

The conventional structures used for phase shifters employ quadrature voltage injection controlled by means of on-load tap changers that require considerable maintenance. Line-commutated thyristor structures have been proposed to replace tap changers, but problems related to filter requirements or the number of switches have limited their utilization. This paper proposes a pulse width modulation (PWM) quadrature-booster phase shifter based on a force-commutated AC controller. It offers features such as fast dynamic response, continuous variation of the phase angle with low harmonic injection, and it requires a simple power structure and can be controlled by adjusting the duty cycle of the switches. The operating principles of the proposed phase shifter are analyzed and their feasibility is demonstrated through digital simulation and experimental implementation