Reflection Phase Shifter Research Articles

Using Reconfigurable Transmitarray to Achieve Beam-Steering and Polarization Manipulation Applications

A reconfigurable transmitarray with beam steering and polarization manipulation capabilities is presented. The transmitarray element consists of an active side, a 360° reflective phase shifter, and a passive side. The active side is made of a polarization tunable patch structure, which can radiate electromagnetic wave at dual linear polarization. The passive side composed of a two-layer patch structure is unitized as a receiver cell. We adopt ${8} \times {8}$ unit cells to construct the whole transmitarray, and then place it above a horn antenna. The measured results show that the transmitarray-based horn antenna achieves beam steering with the scan range of $\pm {60}^\circ \times \pm {60}^\circ $ at 5.4 GHz, and this steering capability can be realized in two orthogonal linearly polarized modes. The polarization manipulation capability of this transmitarray is then studied, and it is found that four different output polarization modes, including two circular polarizations [right-handed circular polarization (RHCP) and left-handed circular polarization (LHCP)] and two linear polarizations, can be obtained over an 8.5% fractional bandwidth, with cross-polarization ratio larger than 15 dB.

Reconfigurable Parasitic Element Antenna Using Reflection Phase Shifters

This letter presents a simple reconfigurable antenna concept, which is based on the influence of reflection phase shifters on the mutual coupling to the parasitic elements. The developed antenna operates in the Industrial, Scientific and Medical band (ISM) at frequency of 2.45 GHz. The objective of this work involves the development of a generic and low-cost reconfigurable antenna, with a 1-D or 2-D layout. The parasitic elements are loaded with varactor phase shifters, and the global synthesis is performed through different radiation pattern objectives. In this letter, we have limited these objectives to two opposite directions as we considered only a 1-D layout. The design has been manufactured and measured. A comparison between the measured and the simulation results shows a very good agreement.

Non‐dispersive tunable reflection phase shifter based on non‐Foster circuits

A new non-dispersive tunable reflection phase shifter is introduced based on the artificial magnetic conductor (AMC) loaded with non-Foster circuits (NFCs). An AMC structure circuit model is extracted and the possibility of mitigating its intrinsic strong dispersion is discussed by loading it with both negative capacitance and negative inductance. The NFC is designed to produce the negative capacitance and inductance based on highly accurate, scalable measurement-based models, and co-simulated with a realistic model of the AMC. The numerical results are in good agreement with the analysis and show a nearly flat reflection phase from 450 to 600 MHz. This flat reflection phase can further be tuned by tuning the loaded inductance from 30 to 50 nH. This investigation paves the way towards a dispersion-less reflection phase shifter design.

Analysis of wire-bonded multiconductor transmission line-based phase-shifting sections

The theoretical analysis of wire-bonded multiconductor transmission lines (MTL) for synthesizing phase shifters is accomplished and generalized in order to extend the traditional theory where 3-dB quarter-wavelength directional couplers are usually employed. In this paper, it is demonstrated that this kind of reflection phase shifters, where the coupled and direct ports are terminated with reactive loads, can be designed for any coupling level. Therefore, analytical design equations are derived to compute both the insertion and return losses as well as the operating frequency band as a function of the coupling factor of the MTL. Furthermore, two general equivalent circuits as a function of the number of strips are derived for two particular arrangements, when both coupled and direct ports are open- or short-circuited. These simple equivalent circuits provide some insight into the physical behavior of the MTL and are expedient to the design of filtering structures and and phase shifters. Finally, the validity of the developed theory is assessed by means of measurements. Two critical- and over-coupling open-circuited and short-circuited wire-bonded MTLs and a broadband balun with an operating fractional bandwidth higher than 92% and excellent output isolation are designed, manufactured, and measured.

Compact Tunable Reflection Phase Shifters Using Short Section of Coupled Lines

In the design of reflection-type phase shifters, the coupler that represents the shifter's backbone is usually assumed to be a quarter-wavelength 3-dB coupler. In this paper, a derived theoretical model shows that, for certain values for the odd- and even-mode impedances, a coupled structure with a length that is less than one tenth of a wavelength is sufficient to build a high-performance reflection phase shifter. The presented analysis indicates that reflection phase shifters can be designed with a more compact size and larger phase range compared with the conventional method of using a quarter-wavelength 3-dB coupler. However, the required odd-mode impedance in the proposed design is low (≈10 Ω) , whereas the required even-mode impedance is high (≈200 Ω). To realize those impedances when using parallel-coupled lines, slotted ground and shunt chip capacitor are used. The proposed design is supported by full-wave electromagnetic simulations and measurements. The simulated results show that 0.085λ coupled structure achieves 255° phase range across 36% fractional bandwidth with less than 1-dB insertion loss and more than 10-dB return loss. In another design, a full-cycle phase range is obtained with less than 1.5-dB insertion loss across the same band by using two 0.076λ coupled sections. A manufactured prototype for a full-cycle phase range validates the simulation results and, thus, the proposed method.

Advanced characterization of a W-band phase shifter based on liquid crystals and MEMS technology

In this paper, we present a continuously tunable phase shifter realized in MEMS technology. Varactors with liquid crystal as a tunable dielectric layer underneath gold bridges are used to build a loaded line phase shifter. Measurements show that the phase shifter has a differential phase shift of 92°, a figure of merit (FoM) of 42°/dB and an input matching of −19 dB at 76 GHz.The tuning speed of the phase shifter is measured at different temperatures between 10 and 50°C. The realized phase shifter can be used in combination with MEMS switches in order to build a 360° tunable reflection phase shifter.

Tunable Microwave Phase Shifters Using LTCC Technology with Integrated BST Thick Films

Low temperature co‐fired ceramic (LTCC) reflection and delay line type microwave phase shifters utilizing completely integrated barium strontium titanate (BST) varactors are investigated. Dielectric properties of the screen printed BST paste in 1–8 GHz frequency range are presented. Sintering temperature and time were varied and their effect on the dielectric properties of the film was studied. Phase shifters were sintered at 875°C for 25 min in line with a standard LTCC sintering profile. The relative phase shift of the reflection and delay line type phase shifters were found to be 5 and 11.5° at 2.5 GHz with applied bias field strength of 8 V/μm, respectively.

Effect of the microwave signal power on the controllability of a ferroelectric phase shifter

We consider a microwave phase shifter based on thin-film ferroelectric parallel-plate capacitors operating as a part of a phased array at an elevated microwave power level and for a limited power in the control circuits. To eliminate capacitance modulation in parallel-plate capacitors by an ac field, we propose the separation of the effects of the dc control voltage and the ac voltage based on the symmetry of the capacitance-voltage characteristic of the unit including two capacitors parallel-connected in the ac voltage U ac and series-connected in dc voltage U dc. The experiment shows that for U dc > U ac, the phase of the wave passing through the phase shifter weakly depends on the microwave signal power. The reflection phase shifter is tested for a pulsed power of the microwave signal up to 6 W and a power in the control circuit on the order of 10 μW.

Research of the polarization aberration on Smith prism

Using the law of refraction and reflection of vector form to trace the light direction of propagation in the Smith prism. Be based on it, get the reflection phase shifter δs and δp on every planes, consequently obtain virtue matrix using Jones vector. The distribution of the polarization state of emergent light wave from Smith prism is analyzed when the light is vertical incidence and different azimuth, homochromatism and linearly polarized. The polarization aberration feature of Smith prism is obtained. At last,the detection experiment is done using the Stokes parameter measurement, and gets the consistent result with theory. The text lay the foundation for studying polarization aberration that effects on imaging quality and detection and correction of polarization aberration.

Electronically Reconfigurable Transmitarray at Ku Band for Microwave Applications

An electronically reconfigurable transmitarray device at 12 GHz is presented in this work. This paper highlights the functioning of this kind of device and thoroughly examines the proposed reconfigurable transmitarray. The architecture is discussed along with the design and selection of all the constituting elements and the prototypes for all of them. In order to add reconfigurability to the transmitarray structure, 360° reflective phase shifters were designed, prototyped and validated for direct application. Eventually, a demonstrative prototype for an active transmitarray with phase shifters was assembled, and radiation pattern measurements were taken in an anechoic chamber to demonstrate the capabilities of this structure.

Tunable Passive Integrated Circuits Using BST Thin Films

Preliminary results from our work on compact phase shifters using BaSrTiO 3 thin films are presented. A reflection phase shifter utilizing a lumped element resonator achieved 120 phase shift at 10GHz with m 3.3dB insertion loss. A synthetic transmission line true time delay phase shifter at 5GHz was able to achieve a phase shift of 60 with m 1.1dB insertion loss. These results were obtained in a process suitable for integration with conventional passive and hybrid circuit technologies.

Linear reflection phase shifter with optimised varactorgamma

It is difficult to realise linear microwave reflection phase shifters at frequencies higher than 3 GHz using abrupt junction varactor diodes, since the diode parasitic package capacitance begins to dramatically affect the phase shift linearity. The use of hyperabrupt junction varactor diodes can significantly improve the phase shift linearity at these frequencies. A circuit and the simulation results for a linear reflection phase shifter implementation using hyperabrupt junction varactor diodes at 3.6 GHz are presented.

Strong Non-Linear MCD-Effects Due to Partially Circular Polarized Light Sources

ABSTRACTMost soft x-ray magnetic dichroism studies are carried out with light of mixed polarization. The effect of incomplete circular polarization is usually taken care off by linearly extrapolating the data to Pcirc=l. Using a classical model which includes the polarization factor we show that the MCD-effect, which is the normalized quantity 2(I+-I-)/(I++I-), is highly non-linear with regard to cire. With a specially designed quadruple reflection phase shifter we measured the MCD effect with Pcire<l as well as with Pcirc∼1. MCD spectra of Fe around the M2,3 transition verify our model calculations of the polarization dependence. The data indicate that the observed non-linear response of the MCD-effect to Pcirc can generally introduce large errors in the quantitative analysis of MCD data where spin <Sz> and orbital <LZ> moments are extracted by means of sum rules.

Phase correcting zonal reflector incorporating rings

An array of conducting elements printed on a grounded dielectric substrate functions as an electromagnetic phase shifter. With a fixed substrate and a given operating frequency, the phase shift is determined by the array parameters. In the paper, the spectral domain moment method model for analyzing homogeneous reflective phase shifters with conducting rings as elements is presented, and numerical and experimental results are given. A novel phase correcting Fresnel zonal reflector based on this model is reported. A 43% maximum antenna efficiency and -22 dB sidelobe level were measured in X-band. The bandwidth of the reflector is estimated to be greater than 10%.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A wide-band GaAs monolithic spiral quadrature hybrid and its circuit applications

The design, performance, and circuit applications of a 2-6-GHz GaAs monolithic spiral quadrature coupler are presented. This 90 degrees coupler uses lumped spiral inductors and metal-insulator-metal (MIM) capacitors and is very small in size (14 mil*26 mil). The measured relative phase difference between the coupled and direct port over the 3:1 bandwidth was 93 degrees +or-6 degrees . Applications of this broadband hybrid in reflection phase-shifter, image-reject downconverter, and I-Q downconverter circuits have also been successfully demonstrated based on this structure. >

A dual-varactor analog phase shifter operating at 6 to 18 GHz

An MMIC analog reflection phase shifter which achieves 120 degrees of phase shift from 6 to 18 GHz is described. The phase shifter uses a dual-varactor reflection circuit which allows varactors with a 3:1 capacitance ratio to achieve the performance that normally requires 10:1 diodes. The varactor diode is a surface-oriented structure with a hyperabrupt doping profile selectively ion implanted to a depth of 0.70 mu m.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Stratified Media and Total Reflection Phenomena

General recurrence relations for the deduction of the reflection and transmission coefficients of a stratified medium are derived. These are suitable for numerical computations on such layered systems involving complex indices of refraction and oblique incidence. The results are applied to total reflection phenomena involving the presence of a dielectric, a perfectly reflecting, or a metallic medium in the less dense medium beyond the totally reflecting boundary. Numerical results are given on a total reflection attenuator, on a total reflection phase shifter, and on a total reflection polarizer. These indicate the potential use of such total reflection phenomena for optical components and laser applications.

Optimization of Diode Structures for Monolithic Integrated Microwave Circuits

Device requirements of a medium power Ku-band reflective phase shifter are reviewed indicating a requirement for a diode with a 4-Terrahertz cut-off frequency. Various structures are examined to test their suitability for integration and feasibility for meeting specifications. A "pocket version" of a surface oriented device design is chosen and described. It is shown to meet or exceed all electrical requirements while providing for compatibility with final integration into the circuit.

Optimization of diode structures for monolithic integrated microwave circuits

Device requirements of a medium power Ku-band reflective phase shifter are reviewed indicating a requirement for a diode with a 4-Terrahertz cut-off frequency. Various structures are examined to test their suitability for integration and feasibility for meeting specifications. A "pocket version" of a surface oriented device design is chosen and described. It is shown to meet or exceed all electrical requirements while providing for compatibility with final integration into the circuit.

Optimization of Diode Structures for Monolithic Integrated Microwave Circuits

Device requirements of a medium power Ku-band reflective phase shifter are reviewed indicating a requirement for a diode with a 4-Terrahertz cut-off frequency. Various structures are examined to test their suitability for integration and feasibility for meeting specifications. A "pocket version" of a surface oriented device design is chosen and described. It is shown to meet or exceed all electrical requirements while providing for compatibility with final integration into the circuit.