Electrically Steerable Single-Layer Microstrip Traveling Wave Antenna With Varactor Diode Based Phase Shifters

The design of a 7-coupled microstrip line 45/spl deg/ phase shifter is proposed in this paper. Tunability was achieved by utilizing the characteristic that the relative dielectric constant of ferroelectrics depends on the applied bias voltage. To obtain a large tuning range of the phase shifter, we added many couplings within the allowable loss range. In terms of control voltage, we applied 0 V and 150 V respectively to inspect the variance of phase shift. At 16 GHz and 0 V, DPS (differential phase shift) is 45/spl deg/. But at the same frequency and 150 V, DPS is 126/spl deg/. Thus, the tuning range of the phase shifter reaches 81/spl deg/. Our frequency band of interest is from 15 GHz to 16.8 GHz. As a result of simulations, RL (return loss) is larger than 19 dB and IL (insertion loss) is less than 2.7 dB with both 0 V and 150 V in this frequency range. The size of the tunable phase shifter is 7.4 mm /spl times/ 2.2 mm /spl times/ 0.5 mm.

This paper is concerned with the use of phase shifters in steerable antennas when there is a need to change the orientation of the radiation pattern. There are a number of types of phase shifters but, for phase shifts above 90 degrees, transmission or reflection type phase shifters offer prefered solutions. The difference in performance between these two types of phase shifters does not appear to be very significant, but transmission type phase shifters may have an advantage in offering phase shifts less affected by the load characteristics, while the reflection type phase shifter is controled by two pin diodes only (instead of three) which may lead to a somewhat less expensive design. In this paper we focus mainly on the behaviour of different reflection type phase shifters design and we present some experimental results for an phase shifters in the 1.5 and 18.5 GHz bands.

The present study discusses the design of microelectromechanical systems (MEMS)-based phase shifters and their application in phased array antenna (PAA) realization. Commercially available MEMS Single-Pole-Double-Throw (SPDT) switches have been employed for the phase shifter design at a frequency of 5.7 GHz (ISM band). These phase shifters are in turn integrated with the feed lines of a 4 × 1 planar patch antenna array such that electronic mode of antenna beamsteering is resulted. It has been observed that a progressive phase shift of 45° between successive patch antenna elements would generate 11° beam tilt with good directivity and a high gain of 9.5 dB. The entire PAA structure along with the antenna elements, phase shifter modules, and the corporate feed network are integrated on the same PCB laminate, Rogers Ultralam 2000™ having permittivity e r = 2.5, thickness h = 30 mil (0.762 mm), and a dissipation factor tan δ = 0.0019 in order to facilitate simplicity in fabrication process.

A frequency-tuning negative-conductance (-G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) boosted structure and applications for a voltage-controlled oscillator (VCO) is presented in this paper. Analog tuning varactors connected to a -G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> boosted structure is proposed to significantly alleviate the limitation of the tuning range for the -G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> boosted structure, resulting in a low-voltage low-power wide-tuning-range VCO. Based on the proposed architecture, the fabricated 0.18-μm CMOS VCO exhibits a measured 49.8% tuning range. Operating at 0.65 V low supply voltage, the VCO core consumes 2.37-mW dc power. At this bias condition, the measured average value of phase noise for all frequency ranges is -115.1 dBc/Hz at 1-MHz offset from the carriers. Relative to recently published wide-tuning-range CMOS VCOs, the proposed VCO simultaneously achieves low supply voltage, low dc power dissipation, low phase noise, and a wide tuning range, leading to a good figure-of-merit (FOM) and FOM including the tuning range. Furthermore, formulas of analysis for the proposed frequency-tuning -Gm boosted structure and wide VCO tuning range are presented, and the mechanisms are validated by experiments.

Recent advances in ferroelectric and high temperature superconductive technology have enabled new phase shifters incorporating ferrite, ferroelectric, and high temperature superconductor materials to be developed. Each material offers important and unique properties which may be combined with one of the other materials to obtain useful phase shifters. Ferrite materials with tunable magnetic permeabilities have classically been used for phase shifters. Ferrites offer large phase shifts with small changes in insertion loss. Ferroelectric materials employing variable dielectric constants can also be used as phase shifters. One advantage of ferroelectric phase shifters over ferrite phase shifters, ultra-wideband performance, enables coverage of the entire band from 2 to 18 GHz. Superconductors offer low losses and unique properties including the kinetic inductance effect and SQUIDs. The physics of the three materials will be reviewed briefly, and the difference between ferroelectricity and ferromagnetism will be discussed. Combination of magnetic and superconducting materials is possible, despite the fact that magnetic fields suppress superconductivity. A comparison of variable time delay and phase shift devices will show interesting contrasts between these devices and MMIC components. Superconducting phase shifters using only superconducting properties, and phase shifters combining superconductivity with ferrites or ferroelectrics will be described.

This paper presents a smart suit, water impermeable, containing sensors and electronics for monitoring handicapped people at hydrotherapy sessions in swimming-pools. For integration into textiles, electronic components should be designed in a functional, robust and inexpensive way. Therefore, small-size electronics microsystems are a promising approach. The smart suit allows the monitoring of individual biometric data, such as heart rate, temperature and movement of the body. Two solutions for transmitting the data wirelessly are presented: through a low-voltage (3.0 V), low-power, CMOS RF IC (1.6 mm x 1.5 mm size dimensions) operating at 433 MHz, with ASK modulation and a patch antenna built on lossy substrates compatible with integrated circuits fabrication. Two different substrates were used for antenna implementation: high-resistivity silicon (HRS) and Corning Pyrex #7740 glass. The antenna prototypes were built to operate close to the 5 GHz ISM band. They operate at a center frequency of 5.705 GHz (HRS) and 5.995 GHz (Pyrex). The studied parameters were: substrate thickness, substrate losses, oxide thickness, metal conductivity and thickness. The antenna on HRS uses an area of 8 mm², providing a 90 MHz bandwidth and ~0.3 dBi of gain. On a glass substrate, the antenna uses 12 mm², provides 100 MHz bandwidth and ~3 dBi of gain.

Miniaturized tunable lasers are important as light sources in optical networks and sensing systems. However, challenges remain in realizing a low-cost on-chip tunable laser with high tuning accuracy and wide tuning range. Here, an external-cavity tunable laser integrated by using a pair of coupled-ring resonators as a reflector onto a single silicon chip is designed and demonstrated. The silicon coupled-ring reflector provides simultaneous tuning of the central reflective wavelength and the free spectral range of the entire cavity to guarantee phase matching. The effective optical length of the coupled-ring reflector is controlled by the complementary thermo-optic and free-carrier dispersion effects, thus enabling high-resolution wavelength fine-tuning while maintaining wide wavelength tuning range. Experimentally, the tunable laser has high external-cavity efficiency (22%) and high wavelength tuning accuracy (2 pm) throughout the 41.6 nm tuning range. Potential applications of the external-cavity tunable laser include optical networks, optical sensing, and on-chip optoelectronic systems.

A new type of phase shifter using cascaded sections of NRI metamaterials and PRI transmission lines has been proposed, which offers some significant advantages over conventional delay lines. The phase shifter is compact in size, can be easily fabricated using standard etching techniques and exhibits a linear phase response around the design frequency. It can incur either a negative or a positive phase depending on the values of the loading elements, while maintaining a short physical length. In addition, the phase incurred is independent of the length of the structure. Due to its compact, planar design, the structure lends itself easily towards integration with other microwave components and devices. It is therefore ideal for broadband applications requiring small, versatile, linear phase shifters.

Abstract- Design and simulation of a very small size 6-bit DMTL phase shifter is presented. The idea is based on using both capacitor and resonator type methods simultaneously in a phase shifter. The capacitor section creates less significant bits. The bits in this section start from the least significant bit, with 5.625-degree steps. The resonator section creates the bits with 90-degree steps. CPW transmission line is used as an impedance matching between two type phase shifters. The structure is calculated and simulated at the Ka-band using MATLAB and HFSS softwares, respectively. The proposed method decreases the number of cells, considerably. As a result, the size and loss is decreased. The design can be easily scaled to other frequencies for satellite and radar systems.

Chip-scale lasers with a wide tunable range and a narrow linewidth have rich applications in optical communications, sensing, and light detection and ranging systems. External cavity lasers (ECLs) have the advantage of a wide tuning range and a narrow linewidth compared with their counterparts such as distributed feedback lasers and distributed Bragg reflector lasers because the passive filter separated from the gain section can be widely tuned and the low-loss external cavity extends the photon lifetime. However, so far, the tuning range achieved by the chip-scale ECLs is in the range of 80–120 nm, smaller than that of the bulk free-space ECL (typically &amp;gt;160 nm). The bottleneck in reaching an ultrabroad tuning range for chip-scale ECLs lies in the unsuppressed side modes of the external cavity. Here, we demonstrate a hybrid-integrated ECL consisting of a broadband III–V reflective semiconductor optical amplifier and a low-loss Si3N4 wavelength-selective reflector. A record 172-nm lasing wavelength tuning range together with a more than 40 dB side-mode suppression ratio is achieved beyond the free spectral range of the Vernier ring filter due to the enhanced lasing mode selection from a tunable Sagnac loop reflector. The Si3N4 platform enables a low-loss external cavity, facilitating laser linewidth reduction below 4 kHz over the full tuning range. The on-chip output power reaches 26.7 mW at a wavelength of 1550 nm.

A conformal cylindrical phased array antenna excited with composite right/left-handed (CRLH) phase shifters is proposed. The phase tuning of the CRLH phase shifter is achieved by embedding novel magneto-static field-responsive micron-sized particles in its structure. It is shown that through the tiny magnet activation of these novel magneto-static particles at appropriate locations along the length of CRLH stub and inter-digital fingers, variable phase shifts are obtained. The proposed particle-based CRLH phase shifter operates in C-band (5–6) GHz with a low insertion loss and phase error. The 1 × 4 cylindrical phased array is excited with the four unit cells of the proposed particle-embedded CRLH transmission line phase shifters to scan the main beam at desired scan angles. A prototype of a 1 × 4 cylindrical phased array excited with the particle-based CRLH phase shifters was fabricated, and the results show that the simulated results are in close agreement with the measured results. The conformal cylindrical array with the proposed particle-based CRLH phase shifters has great potential for use in printed and flexible electronics design where commercially available phase shifters have a definite drawback.

In this paper, we propose a tunable absorber to realize the same range of tuning and the same absorption rate with the same DC voltage in two orthogonal directions. The absorber consisting of a square metal with a gap in diagonal and a varactor diode is highly symmetrical and can induct the same current in x and y polarization, which ensures the identical absorption rate under the same DC voltage. In order to augment the tuning range of the absorber, the detailed analysis is carried out. There is an inevitable problem that the wide tuning range is closely related to the reflection coefficient of proposed absorber. Thus, a compromising dimension is decided to achieve relatively wide tuning range and good reflection in the meantime. The tuning range and absorption rate, respectively, can reach 30.8% and over 95% in simulation.

This paper proposes a hybrid class-AB/class-B voltage-controlled oscillator (VCO) with low voltage, low power, and a wide tuning range. The class-AB VCO core is designed to ensure robust start-up of the class-B VCO core. Featuring a high-efficiency class-B VCO core, the combination of class-AB/class-B VCO cores consumes low dc power. Based on the proposed architecture, the fabricated 0.18-μm CMOS VCO exhibits a measured tuning range of 25.6%. Operating at a low supply voltage of 0.75 V, the hybrid class-AB/class-B VCO cores consume a low total dc power of 2.4 mW. In this bias condition, the measured average value of phase noise for all frequency ranges is -101.4 dBc/Hz at 1-MHz offset from the carriers. Compared to recently published wide-tuning range VCOs, the proposed hybrid class-AB/class-B VCO simultaneously achieves a low supply voltage, a low dc power dissipation, and wide tuning range, leading to a good figure-of-merit including the tuning range (FOMT). In addition, the theories for analyzing the VCO are given in detail, and the mechanisms are validated by experiments.

A sixth-order low-pass transconductor-C filter with a very wide tuning range (fc = 100 Hz to 10 MHz) is presented. The wide tuning range has been achieved without using switchable components or programmable building blocks. A single-stage folded cascode transconductor is employed to implement the proposed filter. A modified biquadratic topology is introduced to improve linearity performance of the filter over its tuning range. Power consumption of the filter scales linearly with cutoff frequency (60 pW/Hz/pole). Implemented in 0.18-μm complementary metal-oxide-semiconductor technology, the filter exhibits relatively constant noise and linearity performance over its entire tuning range and occupies a silicon area of 0.16 mm2 (0.027 mm2/pole).

A fully integrated and differential AlInAs/InGaAs/InP DHBT voltage controlled oscillator (VCO) with wide tuning range and integrated divide-by-2 static divider was demonstrated for 44 GHz wireless and optical communication applications. To our knowledge, these 44 GHz ICs are the highest frequency fundamental mode fully integrated and differential VCOs with wide tuning range ever reported. The 44 GHz fundamental VCO delivers a typical differential output power of +4 dBm at a center frequency of 44 GHz with a tuning range of up to 4.5 GHz. The measured phase noise shows better than -100 dBc/Hz at 1 MHz offset and better than -80 dBc/Hz at 100 kHz offset. We have achieved more than 6 dB improvement in phase noise performance over the differential SHBT VCO results that we reported last year (A. Kurdoghlian et al., IEEE GaAs IC Symp. Dig., pp. 129-132, 2001).