Bandpass Filter Integrated Antennas and Hybrids
|關鍵字:||帶通濾波器;帶通濾波器之合成;濾波天線;巴倫;功率分配器;天線陣列;差動式饋入天線;180度混成器;Bandpass filters;Bandpass filter synthesis;Filtering antennas;Baluns;Power divider;Antenna array;Differential antenna;180 degree hybrid|
In this dissertation, several bandpass filter integrated antennas and hybrids are proposed. Most of the bandpass filter architectures is the coupled resonator type which is made of resonators and admittance inverters. These admittance inverters are realized by EM couplings that result in very compact structures. Bandpass filter responses and multiple additional functions are implanted without occupying any additional circuit area. Special features and advantages of the filtering antennas are discussed. Comparing with the well-matched antennas with the same antenna types, it is proven that the filtering antennas have the better band-edge selectivity, flatter passband radiation responses, higher out-of-band rejections, and generally wider bandwidths. First of all, a series of filtering microstrip patch antennas is discussed. A new gap-feed structure for the microstrip patch antenna is proposed. The radiating patch is excited by another resonator through EM couplings and therefore a two-stage coupled resonator bandpass filter response is achieved. Then a performance enhanced filtering microstrip patch antenna is introduced. Geometrical symmetry leads to the purer polarization and the higher band-edge selectivity. This idea is further extended to microstrip patch arrays. The feeding network, which consists of power dividers and baluns, together with the radiating patches, are served as parts of the bandpass filter design. Next, filtering inverted-L antennas are investigated. We present an extremely simple-structured filtering antenna. This filtering inverted-L antenna is simple to design and easy to build according to its straightforward equivalent circuit. Then, the differential-fed filtering antenna which integrates an inverted-L antenna, a matching circuit, a bandpass filter, and a balun, is proposed. This all-in-one design can be directly connected to an RFIC with a differential terminal without any additional passive components. Finally, two bandpass filter integrated components are exhibited. A compact filtering 180° hybrid, which integrates a balun and a power divider, is proposed. Isolation between ports is achieved by the cancellation of symmetric and anti-symmetric mode operations. Furthermore, a compact filtering Wilkinson power divider utilizing coupled resonators is presented. Output terminals are loaded resister for port isolation.
|Appears in Collections:||Thesis|