analysis of aperture-coupled microstrip antennas with a superstrate using space domain closed form greens functions is presented. integral equations are derived from applying the boundary conditions on the radiating patch, across the aperture, and on the microstrip feedline. the computation of space domain greens functions is performed using the closed-form. the solution of the integral equatio...

Recently there has been a rapidly growing interest in RFID systems and its applications. Operating frequencies including 125 KHz–134 KHz and 140 KHz–148.5 KHz LF band, 13.56 MHz HF band and 868 MHz–960 MHz UHF band were applied to various supply chains. 433 MHz band was decided for active reader and 2.45 GHz band was applied for WiFi reader. Besides the reader antennas, the requirements of tag ...

A two-stage power conditioning circuit consisting of an AC DC converter followed by a DC DC converter is proposed for a vibration-based energy harvesting system. The power conditioning circuit intends to maximize the amount of power extracted from a piezoelectric energy harvester by matching the source impedance with the circuit by adaptively adjusting the duty cycle. An equivalent electrical c...

Most research on wireless power transfer (WPT) has been focused on how to achieve a high-efficiency power transfer. Our study found that under the impedance matching for achieving maximum WPT efficiency, the power transferred to the load cannot reach the maximum when a WPT system is supplied by an AC voltage source with constant amplitude. However, the load power or the voltage across the load ...