Design of Monopulse Comparator Network Using Gap Waveguide Technology at W-Band

This paper presents a monopulse comparator network which is the key component in a monopulse antenna system used for mm wave tracking. It helps in generation of sum and difference patterns necessary for tracking a target. The network is designed based on novel gap waveguide technology. Initially, a magic-tee with 4 ports, is built at W-band with an operating frequency of 94GHz. Reflection coefficients at the ports are better than -10dB. The isolation between collinear and orthogonal ports is around -36.04dB and coupling is near -3dB. The amplitude imbalance is 0.17dB and phase imbalance is within 2 degrees. A monopulse comparator network is designed using 3 magic-tees and a power divider. The proposed low loss network has reflection coefficients better than -10dB at sum, E plane difference (elevation) and H plane (azimuth) ports. Isolation between the sum and difference ports is better than -30dB. The amplitude response of transmission coefficients is near -6dB and phase imbalance is within 2 degrees. The network is designed in three layers and can be manufactured using gap waveguide technology where there is no need to form electric contact.