Phase Shifter Circuit Research Articles

A 1-GHz active phase shifter with a ferroelectric varactor

An active phase shifter circuit implemented with discrete components is reported. The tuning element, a ferroelectric varactor, is a parallel plate capacitor with Ba/sub 0.5/Sr/sub 0.5/TiO/sub 3/ (BST) as the dielectric. The circuit consists of two bipolar junction transistors coupled with a feedback network, which contains the varactor and thus produces a transfer function that can be varied with a control voltage. The active nature of the circuit allows for signal gain, while the BST varactor provides a high-Q tuning element. This represents an improvement over strictly passive phase shifters with ferroelectric elements. Circuit simulation results are presented and compared with measured data from the implemented system. The network, even with markedly nonideal transistors, can provide a true all-pass response over the frequency band of interest (200-1100 MHz). The measurement results demonstrate an analog tunability of about 100/spl deg/ with a gain variation of about 0.6 dB at I GHz when using a BST capacitor with a tunability of 2.75:1.

Dice-Five Polarization-Agile Corner-Fed Patch Array Antenna

A novel planar polarization-agile microstrip subarray is proposed and its performance assessed by a thorough numerical investigation. The subarray consists of five square patches with a central element, directly coupled to a pair of microstrip feed lines by a cross-shaped aperture, which spreads the power outwards to the other patches through a network of suitable connections. By properly exciting the antenna at its input ports, any kind of polarization of the radiated field can be accomplished with fairly low cross-polarization levels. Moreover, since only two feed lines are required to drive the whole subarray, polarization agility is simply and attractively achieved by a single phase-shift circuit. The design concept is described and the results of the analyses and simulations performed by two completely independent full-wave approaches are presented and discussed.

An X-Band Microstrip Phase Shifter Using an Electromagnetic Bandgap Backplane

A new microstrip compatible phase shifter circuit is introduced. The phase shifter uses a strip-type electromagnetic bandgap (EBG) substrate in place of the solid metal ground plane. Such EBG substrates, when made of ferroelectric materials, can produce variable phase constants useful for phase shifter applications. Test models using two different EBG substrates with dielectric constants of 9.2 and 10.2 showed 44.5 degrees of phase difference with 1.7 dB of added insertion loss at 10 GHz from a line originally 504 degrees long.

High accuracy velocity control method for the french moving-coil watt balance

We describe a novel method of velocity control dedicated to the French moving-coil watt balance. In this project, a coil has to move in a magnetic field at a velocity of 2 mm s−1 with a relative uncertainty of 10−9 over 60 mm. Our method is based on the use of both a heterodyne Michelson’s interferometer, a two-level translation stage, and a homemade high frequency phase-shifting electronic circuit. To quantify the stability of the velocity, the output of the interferometer is sent into a frequency counter and the Doppler frequency shift is recorded. The Allan standard deviation has been used to calculate the stability and a σy(τ) of about 2.2×10−9 over 400 s has been obtained.

Crosstalk fault testing by the built‐in self‐test method with test points and phase shifters

AbstractWith the progressive decreases in size and increases in the speed of VLSI, guaranteeing signal integrity has become important. This paper focuses on crosstalk as a factor responsible for the violation of signal integrity and proposes a method of testing for crosstalk faults. The built‐in self‐test (BIST) method, which can detect crosstalk faults by using an M‐sequence of a linear feedback shift register (LFSR), has been proposed. But since the output of the LFSR is used unaltered as a random test pattern, an insufficient number of crosstalk pulses is excited and some faults escape detection. We therefore propose the use of a new testing circuit which increases the number of crosstalk pulses that are excited and makes possible the detection of faults that were previously undetectable. The new testing circuit uses test points and phase shifter circuits which can output sequences that have arbitrary delays from the M‐sequence. In addition, by changing the simulation method, it also becomes applicable to large‐scale circuits for which such simulations could not be used in the past. We evaluate the detection rate and area overhead for several benchmark circuits and show that the method is effective in detecting crosstalk faults. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 54–65, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20108

Real time robotic tactile sensor system for the determination of the physical properties of biomaterials

A novel tactile sensor system, specifically designed to detect and quantify in real time tissue characteristics in a manner analogous to the human hand, is presented. To date, no modality that is capable of detecting the hardness and/or softness of tissues has been developed. The emerging requirement to build smart robotic manipulation for the next generation of virtual systems, incorporating hand-like-tactile feedback, continues to challenge developers in biomedical instrumentation. To satisfy this need we present a novel sensor system, consisting of a combination of a piezoelectric transducer (PZT) and a pressure sensor element. The system is designed with a feedback circuit, made with a disc-shaped PZT sensor element and a phase shift circuit acting as the oscillating circuit. Upon contact with a test object, this system responds to its physical properties by changing its resonance frequency in accordance with the object’s acoustic impedance. It is suggested that this sensor may prove useful in applications involving robotics in the biomedical field and can be incorporated in the next generation of virtual operating systems.

MEMS 2-Bit Phase-Shifter Failure Mode and Reliability Considerations for Large>tex<$X$>/tex<-Band Arrays

RF microelectromechanical systems (MEMS) switch technology used in the fabrication of phase-shifter circuits is examined from the perspective of failure mode and reliability implications on the performance of large X-band array antennas. Amplitude and phase-state failure probability density functions (pdfs) conditioned on switch probability of failure are formulated for both the hybrid-T (switched line) and coupled-line phase-shifter circuit topologies. The pdfs are used to assess the phase-shifter failure impact on overall array level performance in terms of gain loss and the increase in RMS sidelobe level. Reliability and lifetime implications are addressed through considering a probability of switch failure that increases with cycling. The phase-shifter lifetime switching considerations are related to radar system lifetime beam switching requirements consistent with plausible radar system applications. The key findings are that RF MEMS switch mean time to failure /spl sim/125000 h or longer, consistent with /spl sim/100-125 phase-shifter state switches per second (/spl sim/10/sup 11/ switch operations), are reasonable expectations for RF MEMS phase-shifter technology to meet in order to be considered viable for a broad range of array antenna applications.

Polarization-Agile Microstrip Antenna Array Using a Single Phase-Shift Circuit

A novel polarization-agile microstrip antenna array is proposed, in which the polarization agility from linear to circular polarization for the whole array is realized easily by controlling a single phase-shift circuit. Using the corner-fed square patch element, a new 16 element dual-polarized array with high isolation and low cross-polarization is designed and analyzed by the extended multiport network method. A special FET phase shifter circuit is created, where 0/spl deg/ or 90/spl deg/ phase shift between dual ports is electrically switched. Experimental results are presented to verify the theory, and measured circularly-polarized radiation patterns show a boresight axial ratio of 0.5 dB. Another experiment that connects a low noise amplifier together with the phase-shift circuit is also introduced, realizing both polarization agility and power amplification with one active circuit.

Dual-frequency circularly polarised annular-ring microstrip antenna

The novel design of the circular polarisation (CP) for an annular-ring antenna operated at its TM11 and TM12 modes is presented. The CP radiations of the proposed design are achieved by placing an L-shaped strip connected to two orthogonal sides of the inner boundary of the annular patch. The dual-frequency CP operations are excited by a single probe-feed, and no additional 90° phase shifter and impedance-transformer circuit are required. A prototype of the proposed design was implemented and measured. Measured results show that broadside radiation patterns with good CP characteristics are obtained at the two operating resonant modes. Agreement between measured and numerical results is satisfactory.

Analysis of microwave circuits including lumped elements based on the iterative method

The work presented here introduces lumped elements to an iterative method based on the wave concept combined with the two-dimentional fast Fourrier transformation algorithm known as fast modal transformation (FMT). We extend this method to the analysis of microwave-distributed circuits containing passive or active, linear or nonlinear lumped elements which are characterized by their surface impedance as defined in this article. Simulation results of varactor-tuned filter and phase-shifter circuit examples are compared with the measurement results. Good agreement between simulated and experimental results validates the use of the iterative method for the analysis of planar circuits, including lumped elements. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 269–275, 2003.

Discrimination of Signatures Using Euclid Distances (Application to Electrical Certification)

Handwriting has continued to persist as a means of communication and recording information every day. This paper describes a new discrimination of handwriting signatures with a new ball-point pen-based device. The piezoelectric element is constructed in the ball-point pen and the phase shift circuit is used for the measurement of the writing pressure. The time series data of the writing pressure is changed to the frequency spectrum using Maximum Entropy Method (MEM). MT (Mahalanobis-Taguchi) method is applied to the frequency spectrums of the handwriting signatures for the discrimination between the true signatures and the false signatures. The experimental results show the possibility of the discrimination of the signatures.

Traveling Wave Excitation System for Bladed Disks

Atraveling waveexcitation system is described that wasdeveloped fortheU.S. AirForceResearch Laboratory’ s Turbine Engine Fatigue Facility. The traveling wave system was designed to simulate engine order excitation in stationary bladed disks for the purpose of identifying forced response localization and amplie cation due to mistuning.Thesystemcantestbladed disksofvarying sizesand numberofbladesusing eitheracousticormagnetic excitation. A phase-shifting circuit reduces signal generation costs over purchasing separate function generators and allows amplitude and phase calibration of the exciters. Sources of errors in the traveling wave excitation are discussed and estimated. A e nite element analysis shows that the forced response of a bladed disk is more sensitive to structural mistuning than to traveling wave excitation errors. The traveling wave excitation system is demonstrated on an 18-bladed disk, and experimental forced response results are presented. Nomenclature A = force amplitude a = speed of sound C = engine order e = distance error F = force vector Fav = average exciter force magnitude spectrum f = excitation frequency, Hz h = frequency response i = blade number L = wavelength of sound N = number of blades t = time x = forced response 1A = amplitude error 1µ = phase error µ = interblade phase angle µe = phase error ! = excitation frequency

Optimization of Reflection Type Ferroelectric Phase Shifter with Respect to Sensitivity to Statistical Dispersion of Circuit Characteristics at Microwaves

Commercial applications of ferroelectrics at microwaves can be realized in a case of mass production of field effect phase shifters (FEPS), aimed to be element of electronically steerable antennas (ESA). Such phase shifters are designed as microwave integrated circuits based on ferroelectric films. In order to provide a high reproducibility of FEPS integrated circuit, one needs to know how the operational parameters of FEPS are influenced by variation of the phase shifter circuit characteristics. This information is generalized in sensitivity of the phase shifter to statistical dispersion of its circuit characteristics and characterized numerically by tolerance sensitivity factor. The reflection type digital FEPS was investigated. The sensitivity of FEPS was taken as efficiency function of the optimization procedure. It was found that the minimum of the tolerance sensitivity factor is highly dependent on a particular design of the FEPS.

Design and development of ferroelectric tunable microwave components for Kuand K-band satellite communication systems

Integration of a high-temperature superconductor with a nonlinear dielectric ferroelectric such as strontium titanate, i.e., SrTiO/sub 2/ (STO), has created a new class of electrically tunable low-loss microwave components. We have designed and fabricated frequency and phase agile components using a conductor/ferroelectric/dielectric two-layered microstrip configuration. Some examples of these components are: microstrip ring resonators, local oscillators, edge coupled filters, and phase-shifter circuits. These structures have been fabricated using YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// or gold conductor-based microstrip lines fabricated on lanthanum aluminate (LaAlO/sub 3/) or magnesium oxide (MgO) substrates coated with an STO thin film. Frequency and phase agility are achieved using the nonlinear dc electric-field dependence of the relative dielectric constant of STO ferroelectric thin him (E/sub rSTO/). In this paper, we will present an assessment of the progress that our group has achieved thus far toward integration of this technology into wireless and satellite communication systems.

MMIC broadband analog phase shifter and gain circuit for frequency-tunable microwave planar multipole active filter categories

In this paper, a lossless variable gain and analog transmission type phase shifter which consists of a MESFET with series resonant impedances including varactor diodes is designed. The layout, simulated, and measured results of the MMIC chip are presented. The final function of this original monolithic circuit is to be introduced in ring resonator multipole planar filters to tune the frequency response and to compensate for the intrinsic losses of the resonators. The frequency tunability of these new selective active filters is better than one octave bandwidth. As also shown, these phase shifters can be used for the design of a recursive and transversal structure. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 311–318, 2000.

BaSrTiO/sub 3/ interdigitated capacitors for distributed phase shifter applications

In this letter, BaSrTiO/sub 3/ (BST) interdigitated capacitors on sapphire substrates have been investigated. The tunability and quality factor of interdigital capacitors have been optimized for microwave and millimeter wave applications. A monolithic K-band phase shifter circuit that employs voltage tunable BaSrTiO/sub 3/ (BST) interdigitated capacitors is presented here.

K-band 3-bit low-loss distributed MEMS phase shifter

In this work, we present a 3-bit K-band distributed phase shifter circuit that employs microelectromechanical systems (MEMS) capacitive switches. The measured results demonstrate an average 1.7 dB insertion loss at 26 GHz with return loss better than -7 dB. Insertion phase shifts of all switching states are measured and show phase error less than 8.50 for all states. The low loss K-band 3-bit phase shifter demonstrated here can potentially be extended to more-bit-controlled phase shifter applications.

Monolithic Ka-band phase shifter using voltage tunable BaSrTiO/sub 3/ parallel plate capacitors

Monolithic Ka-band phase shifter circuit that employs voltage tunable BaSrTiO/sub 3/ (BST) parallel plate capacitors is presented here. The circuit is capable of continuous 0/spl deg/-157/spl deg/ phase shift at 30 GHz with an insertion loss of only 5.8 dB and return loss better than 12 dB. In addition to promising loss performance (27.1/spl deg//dB) at 30 GHz, the circuit reported here has several advantages over previously reported BST phase shifters such as moderate control voltages (20 V), room temperature operation, and compatibility with monolithic fabrication techniques.

Low-loss distributed MEMS phase shifter

This letter presents a one-bit low-loss K/K/sub a/-band phase shifter circuit that employs microelectromechanical systems (MEMS) capacitors. The measured results demonstrate a delay line with a 180/spl deg/ phase shift/1.l7 dB loss phase shift at 25 GHz, 270/spl deg/ phase shift/1.69 dB loss at 35 GHz, and a return loss better than 11 dB over a 0-35-GHz band. The state-of-the-art insertion loss performance, 154/spl deg//dB at 25 GHz and 160/spl deg//dB at 35 GHz, demonstrates the potential for the implementation of a very low-loss multibit digital MEMS phase shifter.

A comprehensive review of microwave system requirements on thin-film ferroelectrics

The dual aspects of the relationship between microwave system requirements on thin-film ferroelectric (TF-FE) loss tangent (tanδ) and dielectric tunability (δεr,eff) and the performance enhancements TF-FE in turn offers as compared to existing technologies is comprehensively covered. Communication and sensor system requirements on TF-FE-based oscillators, filters, phase shift and true-time-delay phase shift circuits are thoroughly explained for many system-and-circuit combinations, and quantified where possible. In general, if TF-FE tanδ and Δεr,eff are low and high enough respectively, it can replace existing non-tunable, switched assemblies, resulting in lower size, weight, power, complexity and cost, especially as bandwidth widens. While there is substantial application-dependent variation, requirements on TF-FE performance as a function of system-circuit combination can be discerned. Of all four circuits, oscillators need the lowest tanδ (< 0.01) and modest Δεr,eff (< 4:1). Filters and phase shifters need modest tanδ (0.1 to 0.02) and Δϵr,eff, while true time delay requires modest tanδ and the highest Δϵr,eff, (4:1 - >10:1).