Line Phase Shifter Research Articles

A broadband Wilkinson balun using microstrip metamaterial lines

A metamaterial balun that converts a single-ended input to a differential output over a large bandwidth is presented. The device also exhibits excellent return loss, isolation, and through characteristics over the same frequency band. The balun comprises a Wilkinson divider, followed by a +90/spl deg/ negative-refractive-index (NRI) metamaterial (MM) phase-shifting line along the top branch, and a -90/spl deg/ MM phase-shifting line along the bottom branch. Utilizing MM lines for both the +90/spl deg/ and -90/spl deg/ branches allows the slopes of their phase responses to be matched, resulting in a broadband differential output signal. The theoretical performance of the balun is verified through circuit simulations and measurements of a fabricated prototype at 1.5 GHz. The MM balun exhibits a measured differential output phase bandwidth (180/spl deg//spl plusmn/10/spl deg/) of 1.16 GHz (77%), from 1.17 to 2.33 GHz. The measured isolation and return loss for all three ports remain below -10 dB over a bandwidth in excess of 2 GHz, while the output quantities |S/sub 21/| and |S/sub 31/| remain above -4 dB from 0.5 to 2.5 GHz.

An Improved Design for Ka-Band Phase Shifter Using Distributed MEMS Transmission Line Structure

The paper presents a model which describes the stage circuit of Distributed MEMS Transmission Line (DMTL) phase shifter at Ka band and an approach for DMTL design utilizing the saw-shaped coplanar waveguide(CPW). The result of circuit simulation and full wave analysis prove that the model is in good agreement with theoretical analysis. The model can effectively simplify the design complexity after optimization. Simulation results show that the S11 and S21 can achieve -20 dB and -2.5 dB, respectively, and the phase shift arrives at −180 ◦ at Ka band. Comparing with literature data, it has been predicted that S11 improves about 8 dB and the phase shift can increase about 100 ◦ in the same condition.

A New Millimeter-Wave Printed Dipole Phased Array Antenna Using Microstrip-Fed Coplanar Stripline Tee Junctions

A new millimeter-wave printed twin dipole phased array antenna is developed at Ka band using a new microstrip-fed CPS tee junction, which does not require any bonding wires, air bridges, or via holes. The phased array used a piezoelectric transducer (PET) controlled tunable multitransmission line phase shifter to accomplish a progressive phase shift. A progressive phase shift of 88.8/spl deg/ is achieved with the 5 mm of perturber length when the PET has full deflection. Measured return loss of the twin dipole antenna is better than 10 dB from 29.5 to 30.35 GHz. Measured return loss of better than 15 dB is achieved from 30 to 31.5 GHz for a 1/spl times/8 phased array. The phased array antenna has a measured antenna gain of 14.4 dBi with 42/spl deg/ beam scanning and has more than 11 dB side lobe suppression across the scan.

Coupled Microstrip Line Ferroelectric Phase Shifter for Ka-Band Phased Array Antenna

This work presents the design, fabrication and microwave performance of coupled microstrip line phase shifter (CMPS) based on (Ba,Sr)TiO3 (BST) thin films for Ka-band phased array antenna. Ferroelectric BST thin films were deposited on MgO single crystal substrates by pulsed laser deposition. Because this CMPS design can bear the high dielectric constant of ferroelectric thin films at Ka-band, it has many advantages like the high tunability and the low loss. This design is proposed as a component in low-cost beam scanning phased array antennas. Though methods for calculating the characteristics of coupled line are well known, coupled line on the ferroelectric thin film is difficult to analyze because of the high dielectric constant and very thin thickness with respect to that of MgO substrate. So the coupled line on ferroelectric thin films was analyzed here simply using even and odd mode propagation concepts of coupled line by full-wave electromagnetic simulation. The measured results were in good agreement with the simulated results at the frequencies of interest. The measured differential phase shift based on BST thin films was 45° and the insertion loss decreased from −5.7 dB to −3.6 dB with increasing the bias voltage from 0 to 200 V at 30 GHz.

Novel phase shift line in feedforward circuit using photonic bandgap

AbstractIn this paper, a phase shifter with a shifting photonic bandgap (PBG) cell is designed and fabricated in the main loop of a linear feedforward circuit. A portion of the PBG cell is designed for phase shift in the tuning phase. The shifting PBG cell has been applied in the feedforward main loop in order to cancel the main two‐tone signals. The complete cancellation of the main signal is obtained in the main signal loop of a linear power amplifier. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 357–359, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11059

Millimeter-Wave Loaded Line Ferroelectric Phase Shifters

Ferroelectric loaded line phase shifters operating at millimeter waves for phased array antenna applications are presented. Phase shifters were manufactured on using Ba0.3Sr0.7TiO3 thin films. The magnetron sputtering process was used to fabricate these Ba0.3Sr0.7TiO3 ferroelectric films with a thickness ∼1 μm. The phase shifter operating at V-band (60 GHz) demonstrated continuous phase shift up to 220 deg and figure of merit (FOM) 22 deg/dB. The phase shifter operating at Ka-band (30 GHz) showed phase shift up to 360 deg and FOM 40 deg/dB.

Influence of Narrow Transverse Slit in Ferroelectric Based Voltage Tunable Phase Shifter

We report on gold/Ba0.5Sr0.5TiO3 (BST) ferroelectric thin film Ku-band phase shifters designed and fabricated on MgO substrates using two different structures; the coplanar waveguide (CPW) meander line phase shifter and the new phase shifter with narrow transverse slits in the ground plane of the CPW structure. The ability of these devices to provide a variable phase shift is based on the change in dielectric constant of BST with an applied dc bias. The phase shifter with narrow transverse slits showed larger phase shift capability than that of the conventional meander line phase shifter. In the former phase shifter, the phase shift of about 10.6 as a maximum value for the frequency range from 16 GHz to 18 GHz was obtained. In the latter, the phase shift of 9.7 deg at 18 GHz and at an applied voltage of 30 V was measured.

Reliable method for computing the phase shift of multiline LRL calibration technique

In this paper, a new method for computing the phase shift of lines used in the multiline line-reflect-line (m) calibration technique is presented. The new method is based on a matrix approach to determine the traveling wave /spl lambda/ and uses a reliable criterion to compute the constants a/c and b. The new method overcomes the problem of sign ambiguity of the eigenvalues /spl lambda//sub 1/ and /spl lambda//sub 2/, inherent to the classical method. Another advantage of the new method of computing the phase shift is that the physical length of lines is not needed. The new method computes the line phase shift from the knowledge of the traveling wave /spl lambda/, that is, without previous knowledge of the wave propagation constant.

Design method for antenna arrays employing ferrite printed transmission line phase shifters

Ferromagnetic substrates are attractive for microstrip antenna array applications. An alternative method for using ferrites for beam steering with microstrip arrays is demonstrated. In addition, a method is presented to determine the optimum applied bias field values for maximising the array's beam steering angular span. The method relies on a knowledge of the propagation constant (/spl beta//sub eff/) behaviour within the ferrite substrate, and the finite element-boundary integral (FE-BI) method is employed for extracting /spl beta//sub eff/. Experimental and numerical data are included for validating the evaluation of /spl beta//sub eff/. To account for finite magnet dimensions, a static analysis is conducted to account for field spatial variations associated with the bias field. These spatial variations must be taken into account to properly model the ferrite propagation constant behaviour. Results are shown for this alternative array configuration, which achieves scan angles as large as 18/spl deg/.

Aku-band gold/baxsr1-xtio3/laalo3 conductor/thin-film ferroelectric microstrip line phase shifter for room-temperature communications applications

We report on the performance of a Ku-band gold/Ba0.5Sr0.5TiO3/LaAlO3 (Au/BSTO/LAO) coupled microstip line phase shifter fabricated with a 370 nm thick BSTO film. Two hundred degrees of contiguous relative insertion phase shift (ΔϕS21), with insertion losses of 4.6 dB, were measured at room temperature, 14.3 GHz, and maximum dc voltage of 400 V. These results represent significant progress toward viable compact, low-loss, thin-film ferroelectric-based phase shifters at room temperature. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 53–56, 1999.

First Demonstration of a Periodically Loaded Line Phase Shifter Using BST Capacitors

AbstractPeriodically loaded line phase shifter circuits using voltage tunable BaSrTiO3 (BST) parallel plate capacitors have been demonstrated at X-band. The first such phase shifter circuit was capable of 100° of phase shift with an insertion loss of 7.6 dB at 10 GHz. Subsequently, the monolithic fabrication procedure was refined resulting in an improved phase shifter circuit with 200° of phase shift and an insertion loss of 6.2 dB at 10 GHz. In addition to promising loss performance (32°/dB) at 10 GHz, the circuits reported here have several desirable features such as moderate control voltages (20 V), room temperature operation, and compatibility with monolithic fabrication techniques.

Ferroelectric Tuning of Planar and Bulk Microwave Devices

Benefits of ferroelectric component applications at microwaves is discussed. Experience recently gained in the high-temperature film-production technology has been used for obtaining high-quality ferroelectric tunable components. The disk made from bulk SrTiO3 single crystal covered with double-sided YBa2Cu3Y7 films was used as a high-quality TM010 mode tunable resonator. Planar structures containing thin film ferroelectric layers: planar capacitor, sandwich capacitor, coplanar line, and fin line have been studied. Modeling dielectric response of low-temperature incipient ferroelectrics (SrTiO3, KTaO3) has been applied for simulation of tunable planar structures. The quality factor of a tunable component (QFCT) is suggested to characterize the validity of the component for practical applications. The high-quality planar capacitors are pioneered for the applications. The wide frequency band fin line phase shifter has been studied and simulated. The prospects for applications of ferroelectric planar structures at room temperature is discussed.

Measurement of Spherical Aberration Utilizing an Alternating Phase Shift Mask

A spherical aberration function is measured utilizing an alternating phase shift mask (PSM). First, it is theoretically considered that with a highly coherent illumination, the focus of the alternating phase shift lines and spaces (L/S) pattern is equivalent to that of rays in a small annular area of the reference sphere when the aberration function is axially symmetric in the sphere. Then, the focus variation with the pattern pitch is obtained by a printing experiment that employs an alternating PSM. After a primitive mathematical operation, the aberration function is obtained from the experimentally observed focus variation. The aberration function is examined by investigating various anomalous phenomena observed in the printing with the various resolution enhancement techniques (RETs). The comparison between the experimentally observed phenomena and the predictions based on the calculated images with the measured aberration functions shows fair agreement. Consequently, the validity of this measurement method is confirmed.

Distributed broad-band frequency translator and its use in a 1-3-GHz coherent reflectometer

We present the first frequency translator based on a nonlinear transmission line (NLTL) phase shifter and demonstrate its application in a coherent reflectometer, giving a performance comparable to a commercial network analyzer. Rather than forming shock waves on the NLTL with large signal excitation, we use its voltage-variable delay together with both amplitude and phase linearization to modulate the phase of a small 0.5-3.0-GHz microwave signal. The resultant single sideband modulator exhibits >45 dBc carrier and spurious suppression. This new approach has significant applications in both instrumentation and sensing, particularly because it offers a clear path toward complete integration of a coherent measurement system.

(YBa 2 Cu 3 O 7−δ ,Au)/SrTiO 3 /LaAlO 3 thin film conductor/ferroelectric coupled microstripline phase shifters for phased array applications

We report on the design, fabrication, and testing of novel YBa2Cu3O7−δ/SrTiO3/LaAlO3 (YBCO/STO/LAO) and Au/SrTiO3/LaAlO3 (Au/STO/LAO) coupled microstrip line phase shifters (CMPS). These CMPS were tested at frequencies within the Ku and K bands (12–20 GHz), at temperatures from 24 to 77 K, and at dc voltages (Vdc) from zero to 350 V. A relative insertion phase shift (Δφ) of 390° was measured for an eight-element YBCO/STO/LAO CMPS at Vdc=350 V, 16 GHz, and 40 K. At 77 K, a Δφ ∼260° was obtained for the CMPS at the same bias and frequency. Both results correspond to an effective coupling length of 0.33 cm. At both temperatures, the phase shifter exhibits a figure of merit of ∼30°/dB. To our knowledge, these are the best results published so far at these frequencies where miniaturization, insertion loss, and phase delay are key considerations.

Polysilicon cantilever beam using surface micromachining technology for application in microswitches

Our project is the realization of monolithic loaded line phase shifters for hyperfrequency signals supplying planar antennas. Phase shifters include poly-Si microswitches taking the place of the usual PIN diodes. To this aim, undoped polysilicon cantilever beams were produced by surface micromachining. Results on the stress non uniformity and the stiction problem encountered during the process are reported.

Illusory form with inducers of opposite contrast polarity: evidence for multistage integration.

The perception of brightness differences in Ehrenstein figures and of illusory contours in phase-shifted line gratings was investigated as a function of the contrast polarity of the inducing elements. We presented either continuous lines or line-like arrangements composed of aligned dashes or dots whose spacing was varied. A yes/no procedure was used in which naive observers had to decide whether or not they perceived a brightness difference in a given Ehrenstein figure or an illusory contour in a phase-shifted line grating. The results show that brightness differences are perceived to some extent in Ehrenstein figures with inducers of opposite polarity of contrast; however, the percentage of yes response was systematically lower and response times were longer than for figures with inducers of the same polarity. Phase-shifted line gratings with lines of opposite polarity of contrast yielded stronger illusory contours and shorter response times than those with lines of the same polarity. When the sign of contrast was not the same within a given line of induction, neither differences in brightness nor illusory contours were perceived. The results suggest that the mechanisms that lead to apparent differences in brightness are more sensitive to input of the same contrast polarity, the mechanisms generating illusory contours more sensitive to input of opposite polarity. The data are discussed in the light of a multistage approach to illusory form perception and some implications for cortical models of illusory contour integration are discussed.

STM characterization of InP gratings for DFB laser fabrication

AbstractDiffraction gratings for distributed feedback (DFB) laser devices were characterized by means of a scanning tunnelling microscope (STM) operating in air. The gratings, made of n‐doped InP semiconductor, were prepared using holographic and electron beam lithography (EBL) exposures followed by reactive ion etching (RIE) to transfer the photoresist pattern into the wafer. The grating surfaces were partly shadow‐coated with a thin gold layer, and the line patterns were STM‐imaged on both the coated and non‐coated InP surfaces. Pitches of first‐ and second‐order gratings, including λ/4 phase shift lines and the depth of the holographic second‐order grating, were measured by means of a precisely calibrated piezo‐capacitive STM head, a UV diffractometer and a scanning electron microscope (SEM). A precise STM characterization of the coated line patterns was achieved. As regards the non‐coated surfaces, reliable STM measurements of InP grating pitches were performed without any sample preparation and surface contamination.

A Ka-band GaAs monolithic phase shifter

The design and performance of a GaAs monolithic 180° one-bit switched line phase shifter test circuit for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</tex> -band operation is presented. A self-aligned gate (SAG) fabrication technique is also described that reduces resistive parasitics in the switching FET's. Over the 27.5-30 GHz band, typical measured differential insertion phase is within 10-20° of the ideal time delay characteristic. Over the same band, the insertion loss for the SAG phase shifter is about 2.5-3 dB per bit. The SAG fabrication technique holds promise in reducing phase shifter insertion loss to about 1.5 dB/bit for 30-GHz operation.

A Ka-Band GaAs Monolithic Phase Shifter

The design and performance of a GaAs monolithic 1800 one-bit switched line phase shifter test circuit for Ka-band operation is presented. A self-aligned gate (SAG) fabrication technique is also described that reduces resistive parasitic in the switching FET's. Over the 27.5-30 GHz band, typical measured differential insertion phase is within 10-20° of the ideal time delay characteristic. Over the same band, the insertion loss for the SAG phase shifter is about 2.5-3 dB per bit. The SAG fabrication technique holds promise in reducing phase shifter insertion loss to about 1.5 dB/bit for 30-GHz operation.