VHF Collar Integrated Antenna for Ground Link of GPS Based Location System

This paper presents the design of a low-profile collar-integrated antenna operating at 154.5 MHz for use as a ground link in a GPS-based location system for wildlife tracking. The antenna is a conformal zigzag wire antenna that can be easily integrated into the collar. The power reduction caused by lower gain is overcome by improving the return loss. Input impedance matching at 154.5 MHz, which is the most important factor for return loss improvement, is done by changing the size of the antenna and by using a T-matching method that uses a shorting pin. The antenna efficiency is measured by Wheeler cap method. The design details and comparison of simulation and measurement results are presented.