Research On Ridged Substrate Integrated Waveguide Slot Array Antennas

Substrate Integrated Waveguide (SIW) is a device for the propagation ofelectromagnetic waves, which can provide similar propagation characteristics with ametal rectangular waveguide. Since the concept of the SIW was proposed, it has beenused to design waveguide slot array antennas, and has becoming a hot area of theresearch, because it has not only the advantages of low radiation and low insertion lossthat the traditional metal rectangular waveguide has, but also the advantages ofminiaturization and integration-simplicity that belong to the micro-strip. Employingthe Printed Circuit Board technology, it becomes realizable that the slot array antennasbased on the SIW are manufactured in bulks with lower costs.A narrow frequency bandwidth of the common slot array antenna based on SIWlimits the application to wide band radars. Considering the wider operation frequencybandwidth under the dominant model of the ridged waveguide, a Ridged SubstrateIntegrated Waveguide (RSIW) that has a smaller transverse and a wider operationfrequency bandwidth under the dominant model is designed. In this thesis, the RSIW isadopted to design a slot array antenna which has a relative impedance matchingbandwidth of10%plus. Based on this result, a standing-wave slot array antenna ofwhich the relative impedance matching bandwidth is bigger than16%by setting theslot lengths in an arithmetic progression rule. In addition, a novel travelling-wave arrayantenna based on the standing-wave one is designed. The matching load of thistravelling-wave array antenna is a dipole that is composed of a couple of metal wafersprinted on the same substrate with the slot array. The designed travelling-wave arrayantenna can provide a relative impedance bandwidth of23%plus.All the array antennas designed in this thesis have8slot units and gains of higherthan11dBi，so the novel travelling-wave antenna is in close proximity to thestanding-wave one in the efficiency.All the simulations are operated in the CST Microwave Studio. According to thesimulated results, a standing-wave and a travelling-wave antennas are manufacturedand their reflection coefficients, radiation patterns as well as gains are measured by avector network analyzer in a microwave anechoic chamber. The measured results andthe simulated ones are in good agreement, which indicates that the simulation iscredible. The designed antennas can be used in the terminals of the C-bandcommunication systems.