A shoulder-mounted planar antenna for mobile radio applications

A new planar antenna, suitable for use on a shoulder, has been studied for police and fire service portable radios in the 350-MHz band. This shoulder-mounted antenna, which is a type of planar inverted F antenna (PIFA), features extreme compactness while maintaining a higher gain than that of a conventional whip antenna and small impedance changes in the presence of a human body. The low-profile structure enables the antenna to be unseen when the operator wears a jacket. A prototype of the antenna has been built and tested, and the measured impedance characteristics and the radiation patterns are presented. Emphasis is placed on the effect of the human body. The antenna provides a gain of 5.5 dBd, which is 3.5 dB higher than that of a whip antenna. Field measurements verified the excellent performance under a multiple propagation environment.