Novel Design of Passive Mixer for Communication System

This paper presents design and analysis of micro strip mixer using low pass filter, power divider using open stubs, patch antenna and PIN diode. The simulation response of each element in mixer and measured response of fabricated mixer are presented. Maximally flat Low pass filter with cut-off frequency of 3GHz is used as element of mixer. Modified micro strip patch antenna composed of defected ground, slotted patch, feed point variation and some optimization. Simulation is done using IE3D, Serenade software for various parameters. FR4 substrate with dielectric constant of 4.4 and height 1.6 mm was considered for simulation. Isolation between RF input and output of final design is-29.28 dB and between RF input and LO input is-13.11 dB at frequency of 3 GHz and between LO and mixer output is-13.38 dB at 3 GHz. Simulation and measured results for different parameters are reported.