Recent Advances in Slotted Waveguide Antenna Design for its Use in Modern Microwave Remote Sensing

Microwave remote sensing has gained significant prominence in modern scientific and technological arenas. This chapter delves into the comprehensive exploration of use of slotted waveguide arrays as a pivotal component in microwave remote sensing systems. The investigation revolves around a very detailed comparative analysis between two distinct remote sensors. One is the dual-frequency synthetic aperture radar (DF-SAR) antenna—science payload onboard the Ch-II satellite and is regarded as a cutting-edge remote sensor with outstanding performance. The other is a dual-frequency slotted waveguide array antenna (DF-SWA) with dual polarization capability proposed by the authors and optimized to operate at the same frequencies of the DF-SAR antenna (S-Band at 2.5 GHz and L-Band at 1.25 GHz), thereby facilitating a meticulous systematic analysis and performance assessment. The first stage of the study adapts a conventional slotted waveguide design for both frequency bands. The findings demonstrate the promising potential of slotted waveguide arrays in the realm of remote sensing. However, it becomes evident that the traditional design necessitates specific modifications to enhance its attributes. In the second stage, the research implements 86 enhancements to the conventional designs, such as incorporation of ridged waveguides for aperture blockage reduction, implementation of tapered aperture distribution for side lobe reduction, introduction of sub-arraying for bandwidth enhancement; among other innovations. The subsequent sections of this chapter present the improved results derived from these enhancements. Summing it all up, the results obtained through this study clearly establish the suitability of slotted waveguide arrays as viable sensors in contemporary microwave remote sensing applications. Despite the preliminary nature of this research, the compelling findings invigorate further investigations and innovations with slotted waveguide antenna arrays across diverse modern applications.