Mehrdad Nosrati

A Y-slot wideband circularly polarized antenna for non-contact health monitoring applications

The primary object of this paper is to investigate the polarization mismatch effects between transmitter and receiver antennas in noncontact monitoring applications. It is shown that circularly-polarized antennas have better performance compared to similar linearly-polarized ones in the presence of the human body. A novel y-slot wideband CP antenna is proposed. The antenna consists of a u-shaped feed, a y-slot, and a parasitic stub. Simulation results show a bandwidth of 82% (3-7.2 GHz) for VSWR<;2:1 with a 3 dB axial ratio (AR) bandwidth of 33% (4.6-6.4 GHz). The proposed antenna has a low profile with an overall size of 28 mm×28 mm×1.6 mm.

Experimental study of antenna characteristic effects on doppler radar performance

This paper presents an experimental study to evaluate the effects of antenna radiation parameters on the detection capabilities of a 2.4 GHz Doppler radar used in non-contact vibrometer systems. Four different types of patch antennas and array configurations are implemented on both the transmitter and receiver sides of the system. Extensive experiments using a linear actuator and a metal plate are performed and several interesting and nontrivial results are reported. The optimized antenna configuration is shown to result in the highest signal quality and system performance.

A wideband, high-gain, CPW-fed, circularly-polarized, l-shaped slot antenna array

A single-fed, wideband, circularly-polarized (CP), 2 × 2 antenna array is presented. The array feed design is based on the sequential rotation feeding technique. A compact, wideband, CP coplanar waveguide (CPW) slot antenna is proposed as each of the array elements. It is shown that the proposed antenna performance is significantly enhanced when it is placed in the array arrangement. The impedance bandwidth of the array is 66.7% (from 1.5 GHz to 3 GHz) and its axial ratio (AR) bandwidth is 53.2% (from 1.7 GHz to 2.95 GHz) for AR < 3 dB. The antenna array has a stable radiation pattern and a gain of greater than 6 dBi over the entire CP frequency band. The overall size of the antenna array is 170 mm × 170 mm.

A single feed dual-band, linearly/circularly polarized cross-slot millimeter-wave antenna for future 5G networks

A low-profile, single-fed, dual-band, linearly/circularly polarized antenna for future 5G networks in the millimeter wave frequency regime is presented. The antenna comprises of two truncated-corner square patches. A cross-slot is etched on the inner patch. It is shown that this cross-slot generates additional resonances and lowers the axial ratio (AR) of the radiating structure. The proposed antenna is fed asymmetrically by a two-section microstrip line. The overall size of the antenna is only 8 mm × 8 mm. The proposed antenna operates at 28 GHz and 38 GHz. The antenna is linearly polarized in the lower band with an impedance bandwidth from 27.55 GHz to 28.15 GHz for |S11| < −10 dB. The antenna is circularly polarized in the upper band with an impedance bandwidth from 37.2 GHz to 38.3 GHz for |S11| < −10 dB and axial ratio (AR) bandwidth from 37.1 GHz to 38.1 GHz for AR < 3 dB. The antenna has a stable radiation pattern and a gain of greater than 6 dBi over both frequency bands.

A compact circularly-polarized square slot antenna with enhanced axial-ratio bandwidth using metasurface

A low-profile single-fed, wideband, circularly-polarized slot antenna is proposed. The antenna comprises a square slot fed by a U-shaped microstrip line which provides a wide impedance bandwidth. Wideband circular polarization is obtained by incorporating a metasurface consisting of a 9 × 9 lattice of periodic metal plates. It is shown that this metasurface generates additional resonances, lowers the axial ratio (AR) of the radiating structure, and enhances the radiation pattern stability at higher frequencies. The overall size of the antenna is only 28 mm × 28 mm (0.3 λo × 0.3 λo). The proposed antenna shows an impedance bandwidth from 2.6 GHz to 9 GHz (110.3%) for |S11| > −10 dB, and axial ratio bandwidth from 3.5 GHz to 6.1 GHz (54.1%) for AR > 3 dB. The antenna has a stable radiation pattern and a gain of greater than 3 dBi over the entire frequency band.

Effects of Antenna Characteristics on the Performance of Heart Rate Monitoring Radar Systems

This communication investigates the effects of antenna radiation parameters on the detection capabilities of a continuous-wave 2.4-GHz Doppler radar used in noncontact heart rate monitoring systems. Four different types of patch antennas and array configurations were implemented on the transmitter and receiver sides. Extensive experiments using a linear actuator were performed, and several important observations were reported. A specific configuration of antennas was shown to result in the highest signal quality and system performance. Proof-of-concept experiments on human subjects further validated the suggested results, showing that the recommended antenna arrangement boosts the radar detection accuracy by an average of 11%.This paper presents an experimental study to evaluate the effects of antenna radiation parameters on the detection capabilities of a 2.4 GHz Doppler radar used in non-contact heart rate monitoring systems. Four different types of patch antennas and array configurations were implemented on both the transmitter and receiver sides. Extensive experiments using a linear actuator were performed and several interesting and nontrivial results were reported. It is shown that using a linearly polarized single patch antenna at the transmitter and a circularly polarized antenna array at the receiver results in the highest signal quality and system performance. Proof-of-concept experiments on human subjects further validated the suggested results. It was also shown that using the recommended antenna arrangement will boost the heart rate detection accuracy of the radar by an average of 11%.

A broadband blade dipole antenna for UAV applications

This paper demonstrates design, fabrication and characterization of a broadband blade dipole antenna over a wide frequency range of 20-1200 MHz. A stable radiation pattern is obtained by introducing slots to the antenna structure. The proposed antenna has a very low profile with an overall size of only 71 cm×25 cm. A prototype of the antenna has been fabricated and measurement results agree well with simulations.

Wideband circularly polarized antenna using parasitic strip, stub and slot

A new single-fed, wideband circularly polarized slot antenna is presented. Wideband circular polarization is obtained through the use of a parasitic truncated square patch, parasitic slots, and stubs. The feed line utilizes two matching circuit stubs to achieve wide impedance bandwidth. A parasitic track is used to increase antenna beamwidth and also enhance antenna pattern stability in the higher frequency range. Several parametric studies of the most important parameters are also made. The axial ratio (AR) <;3dB is 49.5% (1.63 GHz to 2.67 GHz) and relative impedance bandwidth is 60% (1.6 GHz to 3 GHz).