Patent ID: 6255993
Filing Date: 2001-07-03
Classification: H01Q

Abstract:
An antenna circuit comprising:an antenna capable of coupling to radio waves having rotational polarization in a frequency band;a signal transmission path having a first end coupled to the antenna; anda signal conditioning circuit having first and second ports coupled to a second end of the signal transmission path, the signal conditioning circuit coupling first signals in the frequency band to an output port of the signal conditioning circuit in response to first radio waves received by the antenna having a first polarization and coupling second signals in the frequency band from an input port of the signal conditioning circuit to the antenna to radiate second radio waves having a second, rotational polarization different than the first polarization, wherein the signal transmission path comprises two quarter-wavelength transmission lines acting as impedance transformers and the signal transmission path includes a first pair of ends coupled to the antenna and a second pair of ends coupled to the signal conditioning circuit.