Gain Enhancement of Dielectric Resonator Antenna Using Electromagnetic Bandgap Structure

High gain antennas are highly desirable for long-range wireless communication systems.In this paper,a compact,low profile,and high gain dielectric resonator antenna is proposed,fabricated,experimentally tested,and verified.The proposed antenna system has a cylindrical dielectric resonator antenna with a height of 9 mm and a radius of 6.35 mm as a radiating element.The proposed dielectric resonator antenna is sourced with a slot while the slot is excited with a rectangular microstrip transmission line.The microstrip transmission line is designed for a 50impedance to provide maximum power to the slot.As a result,the proposed antenna operates at 5.15 GHz with a 10-dB absolute bandwidth of 430 MHz(4.98–5.41 GHz).It is important to mention that the gain of the dielectric resonator antenna is enhanced by the introduction of an electromagnetic bandgap(EBG)structure.In fact,EBG units are placed below the antenna,which enhances the realized peak gain from 5.32 dBi to 8.36 dBi at 5.15 GHz.More specifically,a gain enhancement of 3.04 dB is observed with the introduction of the EBG array.This antenna has several good features such as high gain,compact size,large bandwidth,and lower losses which make it a suitable choice for long-range wireless communication systems.

A Compact Dual-Port Multi-Band Rectifier Circuit for RF Energy Harvesting

This paper presents a compact multi-band rectifier with an improved impedance matching bandwidth.It uses a combination of–matching network(MN)at Port-1,with a parallel connection of three cell branch MN at Port-2.The proposed impedance matching network(IMN)is adopted to reduce circuit complexity,to improve circuit performance,and power conversion efficiency(PCE)of the rectifier at low input power.The fabricated rectifier prototype operates at 0.92,1.82,2.1,2.46 and 2.65 GHz covering GSM/900,GSM/1800,UMTS2100,and Wi-Fi/2.45–LTE2600.The size of the compact rectifier on the PCB board is 0.13λ_(g)×0.1λ_(g).The fabricated rectifier achieved an RF-to DC(radio frequency direct current)PCE of 31.8%,24%,22.7%,and 15%,and 14.1%for−20 dBm at the five respective measured operating frequencies.The circuit attains a peak RF-to-DC PCE of 82.3%for an input power of 3 dBm at 0.92 GHz.The proposed rectifier realizes an ambient output dc voltage of 454 mV for multi-tone input signals from the two ports.The rectifier drives a bq25504-674 power management module(PMM)to achieve 1.21 V from the two-port connection.The rectifier has the ability to exploit both frequency domain through the multi-band operation with good impedance bandwidth and a spatial domain using dual-port configuration.Hence,it is a potential candidate for various applications in radio frequency energy harvesting(RFEH)system.