Patent ID: 8583065

Claim:
An antenna tuning circuit for use with small signal receive signals, comprising: one or more tuning stages coupled to an antenna for receiving a radio frequency (RF) signal, said one or more tuning stages configured in series and/or parallel/series configuration with a single main signal path extending from a single antenna to a single output; wherein each said tuning stage comprises a single PIN diode operative to insert and remove its respective individual tuning stage from said main signal path in accordance with a corresponding respective control signal, wherein each respective PIN diode is connected in parallel across an associated tuning stage for series type tuning stages and connected in series with an associated tuning stage for parallel/series type tuning stages; wherein in each tuning stage, said corresponding control signal is DC coupled to an anode of a respective tuning stage PIN diode while a cathode of said respective tuning stage PIN diode is DC coupled directly to ground without passing through any intermediate tuning stages; and wherein the operating bias point of each tuning stage PIN diode is set by a corresponding current limiting resistor and control signal, said PIN diode operating bias point determining the resonant frequency, bandwidth and input impedance of said antenna tuning circuit, which is different than the natural resonant frequency and bandwidth of said antenna.