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This paper proposes an innovative design approach for a voltage‐controlled (variable) attenuator that allows continuous control of attenuation through analog voltage. Different from fixed attenuators, this work employs PIN diodes and compensated gold wire inductors to configure the attenuation network. It is based in imperfect matching theory, ensuring to obtain the acceptable S‐parameters over the operating band. Measurement results demonstrate effective performance of the attenuator within the voltage range of 0.7–1.03 V. Return losses of the attenuator are all better than 15 dB in the operating range of 10.5–19 GHz. The insertion losses exhibit continuous variation from 2 to 15 dB, requiring only a single controlled voltage to adjust the attenuation value. [ABSTRACT FROM AUTHOR]

In this letter, a novel design of electrically tunable substrate integrated waveguide (SIW) equalizer, based on PIN diodes, is proposed. Compared to previous SIW equalizers, this one introduces PIN diodes that exhibit varying impedance under different direct current (DC) voltages. The equalizing values of the SIW equalizer are directly linked to the DC voltage applied to the PIN diode within a specific voltage range. This feature allows it to be considered as an electrically tunable SIW equalizer. The experimental results demonstrate that the equalizing values are consistently monotonic and adjustable within the range of 1.59–7.56 dB in Ku‐band. This adjustment is attained through a DC voltage step of −0.01 V, applied within the range of 1.23–1.11 V. Additionally, the microwave equalizer is a planar structure that can be conveniently implemented on traditional printed circuit board, resulting in lower costs, easier realization, and integration. This SIW equalizer can be applied in amplitude compensation circuits and networks to compensate flatness dynamically. [ABSTRACT FROM AUTHOR]

In this Letter, a novel empty substrate‐integrated waveguide (ESIW) phase inverter (PI) applied in millimetre‐wave has been proposed. ESIW PI, based on the structural symmetry design, is made of four parts: top cover, middle layer, ESIW PCB, and bottom layer. Owing to the reversed‐phase transmission channel, the phase difference between the two outputs is absolutely equal to 180°. The simulation and measurement results are in a good agreement. In the entire Ka band, the return losses, insertion losses and amplitude imbalance of ESIW PI are better than 12.7, 2.66, and 0.64 dB ± 0.6 dB, respectively. Besides, the phase difference is within 180.5° ± 2.9° in the same frequency band. In addition, the input and output ports are located in the identical circuit plane, which is easy to integrate with other devices and components. [ABSTRACT FROM AUTHOR]

In this Letter, a novel empty substrate-integrated waveguide (ESIW) phase inverter (PI) applied in millimetre-wave has been proposed. ESIW PI, based on the structural symmetry design, is made of four parts: top cover, middle layer, ESIW PCB, and bottom layer. Owing to the reversed-phase transmission channel, the phase difference between the two outputs is absolutely equal to 180°. The simulation and measurement results are in a good agreement. In the entire Ka band, the return losses, insertion losses and amplitude imbalance of ESIW PI are better than 12.7, 2.66, and 0.64 dB ± 0.6 dB, respectively. Besides, the phase difference is within 180.5° ± 2.9° in the same frequency band. In addition, the input and output ports are located in the identical circuit plane, which is easy to integrate with other devices and components. [ABSTRACT FROM AUTHOR]

This study presents a comparative study of several printed antennas having different shapes of the patch (rectangular, square, triangular, trapezoidal, circular, elliptical, and annular ring), suitable for 60 GHz wireless applications. All these microstrip patch antennas have been designed and fabricated on a very thin ceramic substrate to enable a high level of integration with other integrated circuits including passive circuits (such as power dividers, hybrid couplers, and passive filters), and active circuits (such as low noise amplifier (LNA), radio frequency (RF) mixers, and frequency multipliers). In that event, all of those circuits will be incorporated on a single and very small planar substrate to reduce overall size, and to avoid lossy millimetre-wave connectors. To analyse and compare the performances, advanced design system of Keysight Technologies was used for circuits design and simulation. This comparison is based on the obtained results particularly in radiation characteristics and inputs return loss, by determining the main associated parameters such as the bandwidth, voltage standing wave ratio, gain, directivity, efficiency, and cross-polarisation level. This comparative study would be very helpful for RF design engineers to select suitable antenna geometry while designing microstrip patch antenna arrays at 60 GHz millimetre-wave band. [ABSTRACT FROM AUTHOR]

This study presents a compact circularly polarised array using tapered slot antenna fed by a substrate integrated waveguide (SIW) power divider. With the proposed topology, broadband circularly polarised property is achieved and total gain can be increased by controlling the element length, conserving the same footprint area. The different 2 × 2 cell configurations are investigated. Simple and integrated series-parallel SIW feed for the choose cell is presented. A 2 × 2 antenna array is designed and fabricated using SIW E-plane power divider. The measured 10 dB return loss and 3 dB axial ratio bandwidths are 35.65 and 32.3%, respectively. The measured antenna gain is 14.4 dBi at 35 GHz. [ABSTRACT FROM AUTHOR]

A 77-GHz six-port frequency modulated continuous wave collision avoidance radar sensor is proposed. Velocity and range are determined from the slope of the instantaneous phase of radar beat signals. Digital signal processing techniques are developed to overcome DC offset and amplitude imbalance problems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 720–725, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24144 [ABSTRACT FROM AUTHOR]

This paper presents simulation and measurement results of a six-port direct conversion receiver for multipath propagation. Simulation results, using the Norton-Bullington model of the multipath propagation and the receiver computer model, are presented and compared with bit-error-rate (BER) measurement results, performed on a six-port receiver test setup. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 137–141, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20072 [ABSTRACT FROM AUTHOR]