Miniature sub-resonant multi-band VHF-UHF antenna

摘要

A novel antenna system for receiving transmissions in the VHF and UHF frequency bands particularly suitable as a miniaturized antenna for UHF reception, such as of digital video broadcasting transmissions. The antenna system utilizes a combination of three techniques including (1) the use of dialect loading using a high dielectric constant ceramic substrate; (2) an antenna dielectrically loaded and tuned to a significantly higher frequency than desired; and (3) use of a tuning circuit to compensate for the frequency offset of the antenna thereby shifting the resonant frequency to cover the entire band. The antenna is intentionally designed to be too small to radiate at the frequency of interest. The antenna element is then ‘forced’ to be tuned to the desired lower frequency using passive (or active) reactive components as part of a tuning circuit. Multi-band operation is achieved by providing a bypass switch to connect the antenna element either to (1) a first receiver without the tuning circuit (i.e. high frequency tuning) or (2) a second receiver with the tuning circuit (i.e. low frequency tuning).