Patent ID: 6094570
Filing Date: 2000-07-25
Classification: H01P,H03D,H04B

Abstract:
A double-balanced monolithic microwave integrated mixer comprising:a) a substrate;b) a radio frequency microstrip balun formed upon the substrate, the radio frequency microstrip balun comprising:i) a first microstrip conductor formed to generally define a loop;ii) a second microstrip conductor formed so as to be generally parallel to the first microstrip conductor;iii) a third microstrip conductor formed so as to be generally parallel to the first microstrip conductor;iv) a radio frequency input port in electrical communication with one end of the first microstrip conductor of the radio frequency microstrip balun;c) a local oscillator microstrip balun formed upon the substrate, the local microstrip balun comprising:i) a first microstrip conductor formed to generally define a loop;ii) a second microstrip conductor formed so as to be generally parallel to the first microstrip conductor;iii) a third microstrip conductor formed so as to be generally parallel to the first microstrip conductor;iv) a local oscillator input port in electrical communication with one end of the first microstrip conductor of the radio frequency microstrip balun;d) a crossover diode ring formed upon the substrate and having one corner thereof in electrical communication with the radio frequency microstrip balun and having an opposite corner thereof in electrical communication with the local oscillator, an output of the mixer being provided at two remaining corners of the crossover diode ring;e) wherein the radio frequency microstrip balun and the local oscillator microstrip balun provide enhanced electrical isolation between the radio frequency port and the local oscillator port, enhanced spurious response suppression, and enhanced local oscillator noise rejection; andf) wherein the second and third microstrip conductors of the radio frequency microstrip balun and the second and third microstrip conductors of the local oscillator microstrip balun extend more than half way around the loop defined by the first microstrip conductor of the radio frequency microstrip balun and the local oscillator microstrip balun.