Integrated Phase Shifter Research Articles

Stability Formulation for Integrated Opto-mechanic Phase Shifters

Stability of opto-mechanical phase shifters consisting of waveguides and non-signal carrying control beams is investigated thoroughly and a formula determining the physical limitations has been proposed. Suggested formulation is not only beneficial to determine physical strength of the system but also advantageous to guess the response of the output to the fabrication errors. In the iterative analysis of cantilever and double-clamped beam geometrical configurations, the stability condition is revealed under the strong inter-dependence of the system parameters such as input power, device length and waveguide separation. Numerical calculations involving effective index modifications and opto-mechanic movements show that well-known cantilever beams are unstable and inadequate to generate φ = 180° phase difference, while double-clamped beam structures can be utilized to build functional devices. Ideal operation conditions are also presented in terms of both the device durability and the controllability of phase evolution.

Substrate Integrated Waveguide Phase Shifter for Hydrogen Sensing

This letter presents a novel environmental sensor for hydrogen detection. The new sensor is based on a passive microwave substrate integrated phase shifter in which the phase shift of the output signal varies in function of the hydrogen gas concentration. The proposed structure uses tin oxide (SnO2) micro powder as a hydrogen-sensing material and exhibits a phase variation of 19.5° in the hydrogen range of 0 to 1.6%. The substrate integrated sensor presents a new solution for environmental sensing which has the advantage of being passive and having a simple and low-cost manufacturing process.

A compact attenuator integrated phase shifter with switchable trimode operations

This article presents a compact attenuator integrated phase shifter with switchable trimode operations. The proposed structure consists of simple reflection-type attenuator and phase shifter with Lange coupler for wideband performance. The reflective circuits for attenuator and phase shifter are implemented with HEMT's and varactor diodes. By separately adjusting the control voltages for attenuator and phase shifter, the designed circuit can operate in trimode: attenuation-mode, phase shift-mode (PS-mode), and loss variation compensated phase shift-mode (LVC-PS-mode). The proposed circuit is implemented in 0.15-µm GaAs low noise pHEMT process and provides the input and output return losses always better than 12 and 15 dB, respectively. Using LVC-PS-mode, the measured maximum phase shifting range of 80° with the measured insertion loss variation within ±0.05 dB from 15 to 25 GHz can be achieved. The chip size of the fabricated core is about 1.5 × 0.65 mm2 excluding test pads. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1798–1800, 2014

Comprehensive design and analysis of diode laser arrays with an integrated phase shifter

Diode laser arrays integrated with a phase shifter are investigated systematically based on the beam propagation method. Device parameters have been varied to obtain expected mode conversion. The passive waveguide loss and two main factors accounting for varied far-field profiles at different driving conditions are analysed. We demonstrate that on-axis main-lobe emission can be maintained by reducing the phase-shifter length within a certain scope. The far-field angle under the thermal lensing effect is theoretically proved to be nearly diffraction-limited by two-step etching. These optimizations are promising for on-axis nearly diffraction-limited laser emission with a higher output power.

60-GHz 5-bit Phase Shifter With Integrated VGA Phase-Error Compensation

A 57-64-GHz low phase-error 5-bit switch-type phase shifter integrated with a low phase-variation variable gain amplifier (VGA) is implemented through TSMC 90-nm CMOS low-power technology. Using the phase compensation technique, the proposed VGA can provide appropriate gain tuning with almost constant phase characteristics, thus greatly reducing the phase-tuning complexity in a phased-array system. The measured root mean square (rms) phase error of the 5-bit phase shifter is 2° at 62 GHz. The phase shifter has a low group-delay deviation (phase distortion) of +/- 8.5 ps and an excellent insertion loss flatness of ±0.8 dB for a specific phase-shifting state, across 57-64 GHz. For all 32 states, the insertion loss is 14.6 ± 3 dB, including pad loss at 60 GHz. For the integrated phase shifter and VGA, the VGA can provide 6.2-dB gain tuning range, which is wide enough to cover the loss variation of the phase shifter, with only 1.86° phase variation. The measured rms phase error of the 5-bit phase shifter and VGA is 3.8° at 63 GHz. The insertion loss of all 32 states is 5.4 dB, including pad loss at 60 GHz, and the loss flatness is ±0.8 dB over 57-64 GHz. To the best of our knowledge, the 5-bit phase shifter presents the best rms phase error at center frequency among the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> -band switch-type phase shifter.

Electronically controlled optical beam-steering by an active phased array of metallic nanoantennas

An optical phased array of nanoantenna fabricated in a CMOS compatible silicon photonics process is presented. The optical phased array is fed by low loss silicon waveguides with integrated ohmic thermo-optic phase shifters capable of 2π phase shift with ∼ 15 mW of applied electrical power. By controlling the electrical power to the individual integrated phase shifters fixed wavelength steering of the beam emitted normal to the surface of the wafer of 8° is demonstrated for 1 × 8 phased arrays with periods of both 6 and 9 μm.

Circulator-Free Reflection-Type Tunable Optical Dispersion Compensator Using Tandem Arrayed-Waveguide Gratings

A tunable optical dispersion compensator that uses cascaded arrayed-waveguide gratings and an integrated phase shifter is reported. It is a catoptric circuit but does not require a circulator. The dispersion is successfully controlled from +142 to +1148 ps/nm. Error-free transmission is confirmed after dispersion compensation in a transmission experiment using 43 Gbps CSRZ-DQPSK modulation.

42.6 Gbit∕s fully integrated all-optical XOR gate

An SOA-based all-optical high-speed Mach-Zehnder interferometer exclusive-OR (XOR) gate fabricated in a silica III-V hybrid-integration technology platform is demonstrated. The device includes integrated time delays for rapid diffcrential operation as well as integrated phase shifters for fine tuning of power splitters and interferometer bias enabling highly optimiscd XOR gate operation. XOR functionality is verified through inspection of the output pulse sequence and the carrier-suppressed output spectrum. A 2.3 dB penalty for a 42.6 Gbit/s RZ-OOK signal at a 10 -9 bit error rate is observed.

A 5.2 GHz CMOS I/Q Modulator With Integrated Phase Shifter for Beamforming

This paper presents the design of an I/Q modulator with integrated phase shifter for beamforming. It is targeted at 802.11a WLAN. An efficient beamforming architecture with a linearly controlled 360deg phase shifting range is proposed for linear transmitters. The phase shifting takes place in the local oscillator path at three times lower frequency than the carrier. The phase shifters are implemented as vector modulators in an efficient way by utilizing a current reuse technique. All control currents are provided by a single current steering digital to analog converter by means of time multiplexed sample and hold circuits. The circuit, implemented in 0.25 mum CMOS technology, has a 1 dB output compression point of -7.1 dBm and consumes 61 mA. It has a phase shifting resolution of 10deg with a differential accuracy of 2deg.

Design and process considerations for fabricating RF MEMS switches on printed circuit boards

Design considerations and process development for fabricating radio frequency microelectromechanical systems (RF MEMS) switches on microwave laminate printed circuit boards (PCBs) are presented in details in this work. Two key processes, high-density inductively coupled plasma chemical vapor deposition (HDICP CVD) for low-temperature silicon nitride deposition, and compressive molding planarization (COMP) have been developed for fabricating RF MEMS switches on PCB. The effects of process conditions of HDICP CVD on low-temperature nitride film are fully characterized for its use in RF MEMS switches on PCB. Not only can COMP planarize the surface of the photoresist for lithographic patterning over topologically complex surfaces, but also simultaneously create a membrane relief pattern on the surface of a MEMS structure. Several membrane-type capacitive switches have been fabricated showing excellent RF performance and dynamic responses similar to those on semiconductor substrates. This technology promises the potential of enabling further monolithic integration of switches with other RF components, such as antennas, microwave monolithic integrated circuits (MMICs), phase shifters, tunable filters, and transmission lines on the same PCBs reducing the losses due to impedance mismatching from components/system assembly and simplifies the design of the whole RF system. [1416].

Integrated ferroelectric millimeter-wave phase shifters with a periodic structure

Integrated phase shifters with a periodic structure that includes BaSrTiO3 ferroelectric varactors parallel-and series-connected to the transmission line are investigated theoretically and experimentally. The phase shifters are designed for the frequency range 26–32 GHz. The dispersion characteristics and insertion losses in the transmission line of the phase shifters are analyzed with regard to the dependence of the capacitance and loss tangent of the varactors on control voltage and temperature. It is shown that parasitic amplitude modulation in the phase shifters can be suppressed if the connection scheme of the varactors takes into account the voltage dependence of the their loss tangent. In the phase shifters with series-connected varactors, the temperature dependence of the phase shift is much weaker than in those with parallel-connected varactors.

Electromagnetic scanning three element array with integral phase shifters

A structure is presented for a three element beam scanning array where integrated phase shifters are fabricated on ferrite plugs inserted into a microstrip feed network. A combination of permanent magnets and electromagnets are used to achieve beam steering of 30/spl deg/ with coil drive currents of 2A.

Microstrip antenna with integrated phase shifter

Microstrip antenna with integrated phase shifter

Substituted Barium Hexaferrite Films for Planar Integrated Phase Shifters

AbstractThick films of scandium-substituted BaScxFe12−xO19 (x=0, 0.4, 0.6) were deposited by pulsed laser ablation deposition onto A-plane (1120) sapphire (Al2O3) substrates to yield highly oriented films having the crystallographic c-axis ([0001]) in the film plane. Selected films were characterized by x-ray diffraction, electron microscopy, magnetometry and torque magnetometry measurements. These structural and magnetic measurements show that dense films have excellent in-plane uniaxial anisotropies and good square loop behaviors. Such films will be useful for planar latched phase shifters that can be integrated into microwave integrated circuits.

A 20-mA-receive, 55-mA-transmit, single-chip GSM transceiver in 0.25-μm CMOS

This paper presents a low-power 900-MHz GSM transceiver developed in a 0.25-/spl mu/m CMOS technology. The superhet receiver, with a single intermediate frequency at 71 MHz, has an overall worst case noise figure of 8.1 dB, including all filters. The overall gain can be digitally controlled over 98-dB range. The receiver consumes only 19.5 mA from the 2.5-V voltage supply while achieving the required blocking and intermodulation performance. The direct conversion transmitter has a fully integrated phase shifter and provides a 2-mW signal to the power amplifier with a low level of spurious emissions. The transmitted Gaussian minimum shift keying signal has an RMS average phase error <2/spl deg/, and the overall current consumption of the transmitter is 55 mA.

Tensor-based characteristic impedance calculations of microstrips on ferrite-dielectric substrates for integrated phase shifter applications

The influences of tensor parameters on the characteristics of microstrip structures on layered ferrite-dielectric substrates for phase shifter applications are investigated. By fully incorporating the permeability tensor into the numerical model, it is found that the propagation constant, and particularly the characteristic impedance values, are substantially lower than those commonly calculated under the scalar permeability assumption. The variation of the characteristic impedance is presented with respect to magnetisation levels, saturation magnetisations and the thickness of the ferrite layer.

Single-lobed far-field pattern operation in a phased array with an integrated phase shifter

A phased array with an integrated phase shifter which can convert a 180° phase mode into an in-phase mode was demonstrated. An Al2O3 facet coating with a different thickness on each array element was performed. It should act as the phase shifter. A stable single-lobed far-field pattern was obtained from the array with the phase shifter.