Characteristics of body-mounted antennas for personal radio sets

The development of a multiturn loop antenna for a police officer's personal radio set is described. The antenna is small, low profile, lightweight, with dimensions of
2.7 \times 2.7 \times 0.7
in high (
1.06 \times 1.06 \times 0.28
cm), and is tunable over the 150- to 170-MHz band. VSWR and radiation patterns are presented with the antenna mounted on a man's shoulder. The shoulder-mounted antenna characteristics are described with conditions where the man is in standing, stooping, and prone positions, with various head and arm movements, and with light and heavy clothing. Radiation patterns are referenced to a 6-in helical whip commonly used by police officers. Radiation patterns also indicate body absorption loss for loop and whip antennas mounted at waist level as compared with shoulder levels. The instantaneous bandwidth is 1.4 MHz for a VSWR
\leq 3:1
. A dual-frequency model for use in a two-frequency push-to-talk mode, is also shown to be practical.