Integrated millimeter-wave quadrature generator

Abstract

An off-chip signal is provided to a differential branch-line directional coupler implemented entirely on-chip. The coupler produces differential quadrature signals, which are then buffered and applied to a quadrature mixer. The coupler is implemented entirely on-chip using microstrip transmission lines. The coupler is made up of a plurality of rings and a plurality of underpasses connecting ports of the rings, wherein each of the plurality of rings is made up of four branch lines, and each branch line having an electrical length of one-quarter wavelength at the center design frequency. Coupling between the plurality of branch lines of the rings may be varied.

1 - 19 . (canceled)  
   
   
       20 . A method for frequency conversion comprising: 
 inputting a pilot signal;    generating a local oscillator signal from the pilot signal;    providing a coupler comprising a plurality of rings and a plurality of underpasses connecting ports of the rings for generating differential quadrature signals from the generated local oscillator signal using the electromagnetic properties of coupled rings in said coupler; and    mixing a radio frequency signal and the differential quadrature signals.    
   
   
       21 . The method of  claim 20 , wherein the method is performed entirely on-chip.  
   
   
       22 . (canceled)  
   
   
       23 . (canceled)  
   
   
       24 . The method of  claim 20 , further comprising at least one of multiplying and dividing the frequency of the pilot signal to be equal to the frequency of the local oscillator signal.  
   
   
       25 . The method of  claim 20 , further comprising a step of buffering the differential quadrature signals to produce buffered differential quadrature signals.  
   
   
       26 . (canceled)