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In this article, the design and implementation of a low-loss bidirectional microelectromechanical system (MEMS)-like passive beamformer for emerging millimeter-wave (mm-Wave) applications are illustrated. A 4 $\times $ 4 phased-array antenna (PAA) is fabricated employing the proposed beamformer for demonstration. The phase shifter (PS) embedded in the beamformer operates based on the principle of loaded-transmission line (TL) PSs. Slow wave mechanism is employed to shrink the size of the PS. The PS measurement results show the average insertion loss (IL) of 1.3 dB in all the tuning states and the IL variation is 0.9 dB. The PS provides 380° of the phase tuning range in a compact footprint area of 2.4 mm $\times $ 3 mm. The antenna array incorporates slot-coupled patch antennas with left-handed circularly polarized (LHCP) radiation. The operating frequency bandwidth of the antenna system ranges from 28 to 30 GHz to provide co-pol/X-pol discrimination of more than 12 dB for all the steering angles. Measurement results show the beam steering angular range of ± 30° in both elevation and azimuth planes. The measurement results also show the peak directivity of 18.48 dBic and the radiation efficiency of 58% at boresight at the frequency of 29 GHz. The efficiency drops 16% when the steering angle reaches the maximum. [ABSTRACT FROM AUTHOR]

A low-cost and low-profile $Ka$ -band passive phased-array antenna (PAA) using continuously tunable substrate-integrated waveguide (SIW) phase shifter is presented in this article. The phase shifting mechanism is based on perturbing the electric field of the slotted SIW (SSIW) line by putting a high dielectric constant slab over the slot of SIW. A systematic approach based on a simple transmission line (TL) circuit model which can support different modes is developed as a fast method for design optimization. It provides insightful physical understanding of the operating mechanism of the proposed phase shifter. In addition, a fully verified TL model of the $1\times 4$ SIW PAA is presented and used to predict and optimize the overall reflection coefficients and radiation patterns at different scanning angles. The TL circuit model is verified by full-wave simulations. As a design example, a $1\times 4$ SIW-based phased-array is designed, fabricated, and measured to validate phase shifter performance and capabilities. The prototype exhibits a continuous beam scanning range from −20° to +20° covering the whole operating band of 29–31 GHz. [ABSTRACT FROM AUTHOR]

This letter presents a low-cost, low-profile, and high-performance $Ka$ -band continuously tunable substrate integrated waveguide (SIW) phase shifter. The proposed phase shifter consists of a slot cut on the SIW’s broad wall and a high dielectric constant slab over the slot. The phase-shifting mechanism is based on perturbing the electric field of the SIW’s fundamental mode, TE10-like, by putting a high dielectric constant slab over the slot of SIW structure to create slow wave phenomena. A prototype is designed, fabricated, and measured. The fabricated phase shifter exhibits linear phase–frequency response behavior with an average insertion loss less than 1.5 dB with an insertion loss variation less than 0.5 dB over a phase shift range of 275° in the operating frequency band (29–31 GHz). The phase shifter consumes a maximum of 25-mW power. [ABSTRACT FROM AUTHOR]

This article presents a new class of tunable passive two-way phase shifters, which can provide an arbitrary phase shift ratio at two different transmit and receive frequencies ($f_{T}$ and $f_{R}$) simultaneously. The proposed phase shifter uses one control element to control both paths. This architecture consists of two transmit and receive paths and a high dielectric constant slab over the paths. By properly setting the length ratio between transmit and receive lines under the dielectric slab, the proposed phase shifters can realize any arbitrary phase shift ratio. For fast and accurate modeling of the proposed phase shifter, a simple Transmission Line (TL) circuit model is presented in this article and verified by full-wave simulations and measurement. The model can be used for calculating the reflection coefficient and phase shift. In order to prove the concept, two phase shifters, one with equal phase shift ($\Phi _{T}/\Phi _{R}=1$) and the other with the phase shift is equal to the ratio transmit frequency and receive frequency ($\Phi _{T}/\Phi _{R}=f_{T}/f_{R}$), are designed, fabricated, and measured. All results show very good agreement between the proposed TL model, the full-wave solver, and measurement results. This type of phase shifter can be used for many beam-forming antenna systems, such as interleaved arrays, full-duplex arrays, and multiband arrays. [ABSTRACT FROM AUTHOR]

This paper presents a low-profile, high-performance, and low-cost Ka-band circularly polarized (CP) passive phased-array antenna (PAA) system. A $1\times 4$ passive subarray operating at the Ka-band frequency band is investigated, developed, and tested as a possible building block for mobile satellite communication systems. In particular, a CP antenna integrated with a high-performance passive phase shifter is presented and experimentally verified. A new low-cost and low-profile magnetic actuator is proposed to precisely control the phase state of the phase shifter. A 3-D printed polymer package is utilized to enclose the phase shifter and reduce the environmental effects. The proposed CP passive PAA achieves high-performance right-hand CP radiation with high cross-polarization discrimination over a wide scan angle from 0° to ±38° over the frequency band (29.5–30.5 GHz). An axial ratio (AR) < 3 dB is demonstrated over the entire scanning range. Moreover, the measured radiation efficiency is 60% at boresight. The gain drops by 1 dB at ±38° scanning angles. [ABSTRACT FROM AUTHOR]

This paper presents a wideband, low-cost, high-performance, and continuous phase shifter for millimeter-wave (mm-wave) phased array systems. Its operational principle is based on modifying the propagation mode of a grounded coplanar waveguide (GCPW) line by placing a high dielectric constant slab over the GCPW line. The propagation constant and hence the phase shift is varied by changing the air gap height between the GCPW line and the dielectric slab. As a proof of concept, a piezoelectric transducer is used to precisely control this air gap height. A printed circuit board-based phase shifter prototype has been designed, fabricated, and tested at two different frequency bands (19–21 and 28.5–30.5 GHz), which are the downlink and uplink bands, respectively, of the Ka-band two-way satellite communication system. A continuous and almost linear phase–voltage characteristic has been achieved experimentally with average phase shift variations 170° and 260° over the two bands, respectively. The footprint of the proposed phase shifter is 2.1 mm×3 mm, which is quite small and suitable for low-profile mm-wave applications. The average insertion losses over the two bands are <0.53 and 2.35 dB with very low variations±0.22 and ±0.35 dB, respectively. [ABSTRACT FROM AUTHOR]

This paper proposes a compact, low-loss, and low-cost phase shifter for millimeter-wave/sub-THz applications. The basic idea is to perturb the propagation constant of a high resistivity silicon image guide by high-dielectric constant barium lanthanide tetratitanates (BLT) ceramic loading. Three different BLT ceramic samples have been tested. The measured maximum phase-shift variation reaches 150° at 100 GHz with an average insertion loss of 2.85 dB and an insertion loss variation <0.7 dB for a sample of a 5-mm length. The proposed phase shifter has a bandwidth from 95 to 105 GHz. A low-cost fabrication technology has been developed and used to realize this phase shifter. [ABSTRACT FROM PUBLISHER]

A highly efficient millimeter-wave (mmW)/Terahertz (THz) dielectric antenna is proposed. The proposed suspended tapered antenna [made of high resistivity silicon (Si)] is fabricated in a new mmW/THz integrated technology platform called silicon-on-glass (SOG). The fabrication process makes the tapered antenna with deep reactive ion etching of the Si layer of the SOG platform, wherein a part of the glass substrate below the antenna tapered section is etched. The glass substrate below the antenna is etched in hydrofluoric acid (HF 49%) before bonding to the Si wafer. The antenna is designed to radiate both E_x- and E_y-polarizations over the frequency band of 110–130 GHz and features additional advantages including highly linear polarization, high-directivity, integrability, and low-cost fabrication. Numerical and experimental results are presented to validate the high-performance proposed antenna. Experiments show gains of 17.5 dBi at 115 GHz and 18.3 dBi at 128 GHz for E_x^11- and E_y^11-modes excitations, respectively. These two polarizations show measured efficiencies of 94% and 99%, respectively. [ABSTRACT FROM PUBLISHER]

This paper proposes a compact, low-loss, and low cost phase shifter for millimeter-wave phased array systems. The basic idea is to modify the propagation mode of a coplanar waveguide (CPW) by placing a high dielectric constant (40< \varepsilon r < 170) slab on top of it. The phase shift is varied by changing the air gap between the CPW line and the dielectric slab. A piezoelectric transducer has been used to control this air gap precisely. For fast but accurate modeling of the proposed phase shifter, two methods one based on spectral domain analysis and the other based on the conformal mapping have been developed and verified with full wave simulations and measurements. A prototype structure with the operational frequency range from 20 to 40 GHz is presented. The maximum phase shift obtained for the electrically controlled version at 40 GHz is 103 ^\circ with loss variation of 0.2 dB. The total length is 2 mm. [ABSTRACT FROM PUBLISHER]

ABSTRACT In this article, a novel mm-wave dielectric image-guide (DIG) to CPW transition is proposed, fabricated, and successfully tested in the silicon technology. A DIG is implemented on high resistivity Silicon-On-Insulator (SOI) wafer. The image-guide height and handle layer thickness are 500 μm and 130 μm, respectively. An Aluminum coplanar waveguide is patterned over the DIG. The measured transmission characteristics of the transition are in acceptable agreement with the simulation results. A transition (coupling) loss of about 1 dB has been achieved at 60 GHz. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:490-497, 2014. [ABSTRACT FROM AUTHOR]

Millimetre-wave (mm-wave) reflectometry is an efficient technique for diagnosis of human tissue disease such as early stage skin cancer. Two sets of non-invasive and in-package reflectometers operating at 42 and 70 GHz are designed, fabricated and successfully tested with different kinds of samples. The tests are performed for a number of liquids, and pure water at different temperatures. Also, the proposedWR-22 device is tested over skin at different locations. The clinical trial tests are performed on a number of volunteer patients who suffered from Basal cell carcinoma. The proposed devices are easy-to-fabricate, and provide a low-cost solution for fast and accurate skin cancer detection. Furthermore, the proposed technology has the potential to be used for fast tissue inspection during a surgery [ABSTRACT FROM AUTHOR]

A dielectric waveguide-based structure coupled to a whispering gallery mode (WGM) disc resonator is introduced as a low-cost integrable millimeter-wave (mm-wave) bio-sensor. An efficient variational analysis method is developed and applied to the WGM. Three sets of sensors, operating in different ranges of frequency from 85 to 220 GHz, are fabricated and tested. The performance of the fabricated bio-sensor is demonstrated for sensing different concentrations of glucose solution samples at D-band. Also, the sensitivity, selectivity, and repeatability of these sensors are examined. [ABSTRACT FROM PUBLISHER]

The dielectric image guide (DIG) lines have an extremely low loss at the millimeter and sub-millimeter frequencies. Here, we will demonstrate using a dielectric line with a width that is smaller than its height. Both ferrite and Si materials have been used to fabricate circuits to achieve tunable functions. Different millimeter wave components and radiating structures with this new aspect ratio have been developed, fabricated, and tested. Special emphasis has been placed on demonstrating the components and antennas' operation in the 26–35 GHz range, but the design concepts developed here can be easily extended to sub-millimeter wave frequencies. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 2010. [ABSTRACT FROM AUTHOR]