Controllable liquid-crystal microwave phase shifter

An electrically controlled phase shifter is described, which is based on a resonant microstrip structure with a nematic liquid crystal substrate. It is shown that the proposed device can operate in the centimeter and millimeter wavelength range.     

Paraelectric thin films by nanoscale engineering of epitaxy and planar anisotropy for microwave phase shifter applications

Epitaxial and (110) oriented paraelectric thin films of Ba0.60Sro.40TiO3 were grown on (100) oriented NdGaO3 orthorhombic substrates, and the nonlinear dielectric properties were studied at 10 GHz along selected in-plane crystallographic directions in the film thickness range of 25-1200 nm. The measured dielectric properties show strong residual strain and in-plane directional dependence. For instance, the in-plane relative permittivity is found to vary from as much as 500 to 150 along [110] and [001], respectively, in the 600 nm film. Tunability was found to vary from as much as 54% to 20% in all films and directions. In a given film, the best tunability is observed along the compressed axis in a mixed strain state, 54% along [110] in the 600 nm film. It is shown that, by nanoscale manipulation of epitaxy and planar anisotropy, the return loss and phase shift in a paraelectric can be tuned over a rather wide range. The approach presented herein opens avenues for obtaining various degrees of phase shift on the same film, enabling one with an additional degree of freedom in device design and fabrication as well as multifunctionality.     

Monolithic HTS microwave phase shifter and other devices

We describe a monolithic high-temperature superconductor (HTS) phase shifter based on the distributed Josephson inductance (DJI) design integrated monolithically into a 10-GHz microstrip line. This microwave circuit incorporates >1000 HTS rf SQUIDS. Recent data demonstrate the performance of this broadband HTS circuit. We observed phase shifts greater than 150° in resonant structures, and 20° in broadband circuits. The nonlinear inductance of the superconducting transmission line can be used for other novel applications, including parametric amplification. A comparison of the DJI circuit to a series array of Josephson elements (used for pulse sharpening) will contrast these two new and exciting nonlinear transmission line circuits.     

Microwave phase shifter with planar capacitors using strontium titanate films

A design of a microwave phase shifter based on a loaded microstrip line using planar SrTiO₃ capacitors as nonlinear elements is described. The microwave phase shifter (at T=300 K) demonstrated a continuous phase shift between 0 and ∼55 deg in the frequency range 8.6–9.0 GHz with a phase error not exceeding 5 deg. The quality parameter of the phase shifter in the operating frequency range was 110 deg/dB. Pis’ma Zh. Tekh. Fiz. 25, 78–83 (October 26, 1999)     

Design of a vector-sum integrated microwave photonic phase shifter in silicon-on-insulator waveguides

An orthogonal vector-sum integrated microwave photonic phase shifter (IMWPPS), consisting of mode-order converter multiplexers (MOCMs), a variable optical power splitter (VOPS), an optical switch (OS) and fixed time delay lines (FTDLs), was theoretically demonstrated in a silicon-on-insulator wafer. MOCMs, as a key element of our device, were employed to generate orthogonal vector signals and served as lossless optical combiners. Combining with the thermo-optical VOPS, OS and FTDLs, the microwave phase shift of 0～2π could be achieved by a refractive index variation of 0～15×10(-3) in the millimeter wave band. The corresponding tuning resolution was about 1.64°/°C. This work, for the first time to our knowledge, provides an attractive solution to transferring a vector-sum method based bulk MWPPS into a integrated one, which is very important for large-scale optically controlled phase array antenna.     

Ferroelectric (Ba,Sr)TiO3 thin-film 60-GHz phase shifter

The design and microwave characteristics of an integral ferroelectric Ba_0.3Sr_0.7TiO₃ thin-film microwave phase shifter operating in the millimeter wavelength range (f∼60 GHz) are reported. In this frequency range, the device introduces a loss of S ₂₁=−10 dB and allows a continuous phase shift in the interval from zero to 220 deg with a small phase error (not exceeding ±5 deg).     

Failure analysis of the adhesive joint of microwave ferrite phase shifter

Failure investigation is carried out on the adhesive joint of microwave ferrite phase shifter. Though, practically, the failure mode of microwave ferrite phase shifter can be described as the fracture of adhesive joint between ferrite and microwave dielectric ceramic, the failures of adhesive layer could be found in various ways and at various stages of manufacture, assembly and service. They may be due to the strength degradation caused by moisture environment, or the voids defects originated from dehydration effect of the adhesive as well as the contamination during manufacturing. With the help of SEM, FTIR and TGA, both the normal and failed samples of microwave ferrite phase shifter were selected, compared and analyzed. Recommendations for the structural design and the adhesive process are presented, and the responsibility of the failures was charged to the negligence of the manufacturer of the microwave ferrite phase shifters.     

Photonic full-range phase shifter with simultaneous tunable frequency multiplying capability based on a DMZM

In this paper, a novel microwave photonic full-range phase shifter with simultaneous frequency-multiplying capability is proposed. The main device is a dual-drive Mach–Zehnder modulator (DMZM) embedded in a Sagnac loop. Under the assistance of two electrical phase shifters (EPS) and a following polarizer (Pol), the optical carrier is eliminated with desired phase tunable carrier-suppressed double-sideband (CS-DSB) signal reserved. So after photoelectric conversion, the frequency-multiplied phase tunable signals are generated. The frequency multiplication factor (FMF) switching and phase tuning operation of multiplied signals can be achieved easily by adjusting the corresponding EPS. The simulation results show that the proposed structure driven by a 10?GHz RF signal can generate a frequency-doubled signal (20?GHz) or frequency-quadrupled signal (40?GHz) that features full-phase tunable range and flat power response. What is more, the proposed phase shifter has a relatively good robustness to the non-ideal factors, large frequency operation range and good frequency tunable capability.     

A quasi-optical phase shifter based on an active grating for the 8-mm wavelength range

A new quasi-optical phase shifter for the 8-mm wavelength range, which allows the phase of electromagnetic radiation in a wave beam to be controlled, is described. The phase shifter operation is based on the phenomenon of wave phase variation upon reflection from an active grating that is formed by the layers of plasma in channels of a dielectric plate arranged above a flat metal mirror. It is shown that the phase of the reflected wave can be effectively controlled by changing the grating-mirror distance and the gas pressure in the channels. The experimental data are compared to the results of numerical calculations.     

A finline 60-GHz phase shifter based on a (Ba,Sr)TiO3 ferroelectric thin film

The design and microwave characteristics of a ferroelectric thin film slotline-waveguide phase shifter operating in the millimeter wavelength range (f～60 GHz) are presented. In this frequency range, the phase shifter possesses a figure of merit F=32 deg/dB and provides for a continuous phase shift in the interval from zero to 255 deg. The ferroelectric films are characterized by a dielectric loss tangent of tan δ=0.04 at a tunability factor of K≈1.7, which are promising parameters for the given frequency range.     

A planar thin-film SQUID of high inductive coupling constant

An inductive coupling dc-SQUID has been developed which is a thin-film structure containing an input coil, a SQUID proper and a groundplane. The SQUID parameters are sensitive to the thicknesses of insulating layers between these components. The SQUID can provide a high coupling constant between the input coil and SQUID loop.     

基于微波锁相环的Ka波段锁相信号源

采用鉴相器、变容管压控振荡器(VCO)和毫米波倍频器实现了Ka波段低噪声锁相信号源,其中心频率可在37.6～44 GHz之间设定,在39.8 GHz频点的输出功率为16 dBm,抖动均方根值JRMS≈0.8 ps,相位噪声为-94.4 dBc/Hz(100 kHz频偏).该锁相信号源可作为40Gb/s光纤通信系统中的参考时钟,也可用作毫米波雷达、制导系统中的信号源或本振源.     

Novel current-mode all-pass phase shifter using a current conveyor

Using a single second-generation current conveyor (CC II), a current-mode second-order all-pass phase shifter network is proposed. The novelties of the network are the availability of high output impedance, the use of grounded capacitors, and the insensitivity of phase shift relative to the CC II device nonideality     

A polarization-independent and broadband microwave metamaterial absorber based on three-dimensional structure

In this paper, we design a polarization-independent and broadband microwave metamaterial absorber (MMA) based on three-dimensional structure. The simulated results show that the proposed absorber has a broad absorptance band from 60.4 to 100.0 GHz with the absorptance efficiency over 90%. The effective medium theory (EMT), electric field, surface current and power loss density distributions are adopted to explain the physical mechanism of the perfect absorptance. In addition, the absorptance differences can be observed between transverse electric (TE) wave and transverse magnetic (TM) wave at oblique incidence. The proposed absorber can be utilized in many applications such as perfect absorbers and radomes.     

Design and implementation of a substrate integrated waveguide phase shifter

The design and implementation of a phase shifter based on the substrate integrated waveguide (SIW) technique operating at 10 GHz are presented. The proposed phase shifter consists of a SIW section with two inserted metallic posts. The phase shifting in this configuration is achieved by changing the diameter and the position of these posts. Numerical simulations have been carried out for different diameters and positions, which have shown good agreement with the theory. A parametric study was also conducted to assess the impact of errors made on the diameter and position of the two metallic posts. To prove the concept, prototypes were fabricated and measured. Experimental results agree well with simulations and SII was better than -14 dB, S21 better than -1.08 dB and the phase error was less than 1.5deg.