Abstract:
Disclosed is a tunable loop antenna (20) in which the antenna tuning capacitor (36) is an integral component of the antenna structure. In each disclosed embodiment, the loop antenna is of square configuration with the ends of the conductor (22) that forms the antenna loop being spaced apart from one another. Capacitor plates (38 and 40) extend orthogonally from and coaxially surround each end of the loop conductor to thereby define a parallel plate capacitor in which spacing between the capacitor plates and, hence, the resonant frequency of the antenna is controlled by flexure of the antenna structure. Suspended between the capacitor plates is a dielectric plate (48). Dielectric grease (54) fills the gaps between the dielectric plate (48) and capacitor plates (38 and 40). A remotely operable motor-drive unit (54) facilitates tuning the antenna to a desired frequency.