Patent ID: 7298217
Filing Date: 2007-11-20
Classification: G01S,H01Q,H03L

Abstract:
1. A phase shifter, comprising: an input signal source having a frequency f; a coupler fed by the input signal, such coupler having a pair of output terminals for providing a pair of signals having the frequency f and having a relative phase difference of mπ/2 radians, where m is an integer; a switch having a pair of inputs, each one of the pair of inputs being coupled to a corresponding one of the pair of output terminals of the coupler, such switch having an output, one of the pair of inputs of the switch being coupled to the output of the switch selectively in accordance with a first control signal fed to the switch; a tunable resonant circuit coupled to the output of the switch, such tunable resonant circuit having a nominal resonant frequency which is an integer multiple of the frequency f, the frequency of the resonant circuit being detuned from the nominal resonant frequency in response to a second control signal fed to the tunable resonant circuit.