| With the wide application and rapid development of modern wireless communication technology in civil,national defense and other fields,the whole radio system has been put forward higher requirements.As the key components,antenna and filter have significant affection on systems performance.Therefore,it is particularly important to study antennas and filters with low-profile,miniaturization,high integration and high efficiency for microwave and millimeter band.Substrate Integrated Waveguide（SIW）has been widely used in microwave millimeter wave communication due to its advantages of small size,low-profile,high integration and light weight.In this dissertation,the antenna and filter have been studied based on SIW technology for microwave and millimeter-wave applications.The main research contents are as follows:（1）A compact SIW cavity-backed slot self-diplexing antenna is designed.The antenna is an X-band dual-band tunable half mode SIW self-diplexing antenna with 50%size reduction.Two V-shaped slots with different opening directions are etched on the top surface of the antenna as the radiation source.Each V-shaped slot is backed by a quarter-mode cavity.This antenna has the advantages of compact structure,high front-to-ratio,high isolation and no need for additional converters to provide isolation between ports and so on.It can be used for directional antennas such as radio navigation and satellite communication.（2）A cavity-backed slot self-diplexing antenna based on half-mode substrate integrated waveguide（HMSIW）is designed.The principle of HMSIW is used in the design of the antenna.Two rectangular slots of different lengths are etched on the top surface of the antenna.The energy of the antenna is radiated by two rectangular slots to achieve dual-frequency characteristics.Good isolation between the two slots in the operating frequency band is shown in the S-parameter results,but the cross-polarization level of the antenna is relatively poor according to the radiation pattern.On the basis of the above research,the rectangular slot of the antenna was replaced with an L-shaped slot.Finally,the antenna resonance is optimized at 12.81 GHz and 13.89 GHz,the isolation between the two ports is better than-29 d B,the cross-polarization is better than-20 d B,and the maximum gain of across the two-band ports is 6.33 d Bi and 7.62 d Bi,respectively.（3）A miniaturized quarter-mode Fan-Shaped SIW bandpass filter is designed.The bandpass filter is designed based on a SIW cavity with a quarter circular.A metallized via in the center of the circle and a quarter circular ring slot etched along the circumference excites quarter-mode resonance.Independent control of the quarter mode resonant frequency is achieved by one or two radial slots with different lengths etched on the top surface.Multiple zeros are introduced to form a second and third-order bandpass filter with controllable bandwidth and wide stopband.Based on the research and design of the second order Chebyshev filter,a third order bandpass filter is designed,fabricated and measured.The center frequency of the third-order bandpass filter is 1.14 GHz,the relative bandwidth is 35.9% and two transmission zeros are introduced on the right side of the passband. |
