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A novel wearable dual-band MIMO antenna featuring good conformal characteristics under bending conditions is presented. The dielectric part of the antenna is built on a flexible substrate using layered lightweight plain weave fabric Organza with a relative permittivity of 1.63 to achieve a low-light and flabby textile. A defected ground structure (DGS) is employed for improving diverse parameters such as narrow bandwidth and resonant adjusting. The DGS part of the antenna is a resonant slot in the ground layer, placed directly under the patches. The electromagnetic energy is transmitted to the radiating slots using a recessed microstrip line feed along with semi co-planar waveguide (CPW) structure with defective ground metal in the bottom layer. It is worthwhile to point out that using the highly flexible Organza fabric with the ability to change the substrate thickness provided acceptable antenna characteristics under the bending condition in different directions. To validate the design, a prototype antenna is fabricated and experimentally investigated. The effect of substrate thickness on antenna performance is investigated by changing the number of Organza layers in both simulation and experiments. A good agreement is attained between the simulation results and the measurement results. The antenna properties such as scattering parameters, radiation patterns, and SAR values are investigated under bending conditions. Results show that the maximum measured gain is 7.8 dB at 2.4 GHz and 7.3 dB at 5 GHz. The simulated specific absorption rate (SAR) values are less than 0.336 W/Kg and 0.468 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively. The SAR values for the bent antenna are less than 0.302 W/Kg and 0.458 W/Kg at 2.4 GHz and 5 GHz for 1 g human body tissue, respectively. [ABSTRACT FROM AUTHOR]

A compact monopulse antenna array based on substrate integrated waveguide technology is presented through this article. The design is fabricated on Printed Circuit Board (PCB) technology consisting of a double-layered 8-cell array antenna with a slot in the middle-ground metal used for aperture-coupling excitation and reducing unwanted spurious emissions from feed network. The Impedance bandwidth and AR bandwidth are enhanced due to optimal feed network, including Rat-Race coupler to generate sum and difference patterns for mono-pulse applications operating at 10 GHz. The prototype of the proposed antenna with the size of 124*25 mm2 is fabricated and tested. Measured results compared very well to simulation results obtained by CST microwave studio and show −10-dB impedance bandwidth of 4% and −22 dB null-depth in difference mode. [ABSTRACT FROM AUTHOR]