Compact Single-Balanced Mixer Using Microstrip Circular Patch Resonator

Inthis paper, design of a compact single-balanced diode mixer utilizing a microstrip circular patch resonator at 2.4 GHz is presented. The novelty in the design is that the circular patch resonator behaves as a 180 degree hybrid as well as a filter to provide good LO to IF and LO to RF isolations thus makes the mixer configuration compact. The mixer works in down-conversion mode for low-IF operation and provides 6.7 dB conversion loss for +7 dBm local oscillator (LO) power and 330 MHz 3-dB radio frequency (RF) bandwidth. The LO to IF and LO to RF isolation are greater than 28 dB and 23 dB respectively. Design approach of the mixer is outlined in the paper with its simulated and measured results.