Design Of An8mm Slotted Waveguide Planar Array

With the comprehensive applications of millimeter-wave planar slot arrays inradar seekers and the fast developments of millimeter-wave techniques, the study onmillimeter-wave planar slot arrays has been becoming a hot topic in antennacommunity.This thesis focuses on the design and fabrication of a millimeter wave slot arrayantenna. The antenna is required of small size, light weight and a pattern with low sidelobes, which bring about the difficulty of the realization of the antenna. On the basis ofthe principle and theory of the slot array antenna, the technological process isexplicated. The physical model and mathematical model is created. The theory analysisand the performance of the components are deduced and simulated in detail,respectively. The components include the excitation slot, waveguide power divider,coupling array, radiation slots and sum-difference network. The rational error range ofthe key size is proposed after the error analysis is done. The system of the slot arrayantenna is simulated and the design is correctly verified. For the difficult realization ofthe antenna, the design has been experienced a lot of tests to ensure the antenna to beprecisely fabricated.To overcome the difficult fabrication and improve the high precision of the slotarray antenna, some creations have been made and are expressed by four facts. Firstly,the illumination efficiency is ensured and the electric current distribution has a gentlefringe slope by the optimization of the systematical design and the controlling of theside lobes with Taylor weight of the aperture. Secondly, applying the number of thesubarrays of the coupling slots and the resonance states, the data of the impedance ofthe slots is extracted and the accurate coupling parameters of the slot array antennahave been received. Thirdly, a sum-difference component has been proposed by using acoupling slot match difference circuit. In the difference circuit, the match film is notneeded, which decreases the difficulty of the antenna fabrication and improve thebandwidth of the component. Finally, the slot array antenna has five layers with arational arrangement, including half height wave guide, radiation layer, coupling layer, feeding layer and coverage layer. The antenna has a height of10mm(about1.2λ) anda weight of0.3Kg, which save enough spaces for the narrow cavity of the missiles.An8mm waveband two dimensional monopulse planar slotted waveguide arrayantenna is then designded and manufactured. The first manufactured antenna prototypepossesses a good antenna performance, and the measured results agree with thetheoretical results well. The operating frequency bandwidth for VSWR <2is up to2.3GHz, while the sidelobe level in the azimuth or elevation plane is less than-23dB or-25dB, respectively.