Down-Conversion Mixer Using Quadrature Hybrid Couple and Schottky Diode for S-Band Radar Application

In the superheterodyne receiver system needs frequency translation process between the Radio Frequency (RF) signal and Local Oscilator (LO) signal. The process will converts RF to Intermediate Frequency (IF). In this paper, present designed and realized a down-conversion mixer which operates at S-band frequency for coastal-radar application. In the design process, the advanced design system (ADS 2011.11) software is applied to design and simulate it. This mixer has been built by using 90o quadrature hybrid Coupler with single balance technique. Whilst, the realization uses microstrip lines technique and two pieces of SMS 3923 schottky diode. The measurement results has been obtained as follows: 24.42 dB conversion loss at 600 MHz, with -30 dBm of RF signal and 15 dBm of LO signal.