Shorting Pin and Slot Loaded Dual Band Microstrip Antenna for MICS and GPS Applications

Abstract

A simple dual-band antenna for MICS (402-405 MHz) and GPS (1570-1580 MHz) bands is developed and discussed in this paper. The effective shunt inductance property of shorting pin and effective electrical length property of slot is used on a conventional circular patch antenna (CPA) to reduce the resonant frequency of the modes (TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and TM21). A single shorting pin is placed at the periphery to drop down the resonance frequencies. After that 12 equal rectangular slots are incorporated along the circumference of a 24 mm radius circular patch for further reduction hence, the size of the antenna is reduced by 94.73% in compared to the conventional CPA. The measured impedance bandwidth for MICS and GPS band is about 8.9% (384-420 MHz) and 3.17% (1.55-1.6 GHz) respectively. The simulated 3-dB axial ratio bandwidth is about 6.21% (390-415 MHz) for MICS band and 1.9% (1.56-1.59 GHz) for GPS band. This antenna can be very useful for real-time data transmission and tracking the dynamic location of human body, especially for elderly persons. The 50 mm x 50 mm x 1.6 mm proposed antenna is fabricated and measured to validate the simulated results and it shows good agreement.