Balanced BPF Design Using Folded Substrate Integrated Waveguide Cavity

• Main Authors: Yi-Hsien Yang, 楊逸賢
• Other Authors: Min-Hua Ho
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/17431745338631495524

碩士 === 國立彰化師範大學 === 電信工程研究所 === 103 === The objective of this thesis is to study and design balanced band-pass filters (BPFs) using the substrate integrated waveguide (SIW) cavity and folded SIW cavity. In the filter design, we utilize the fundamental mode, TE101, to create the filter’s passband. The higher modes, TE201 and TE102 are managed to be suppressed. The circuit performance mainly relies on the common mode signal suppression, which is also accomplished by the non-responsive hybrid microstrip/slot feed structure. In the first part of this thesis is a 3rd order SIW cavity BPF design. The SIW cavity of TE101 mode operation creates the balanced BPF’s passband. The cavity is excited thru a coupling slot, which is illuminated by a microstrip line. The microstrip feed not only excites the coupling slot, but also performs the TE201 and TE102 suppression and possesses a zero implementation function. The second part of this thesis is to design a folded balanced BPF of 3rd order. To reduce the circuit size, we fold the cavity resonator along it’s middle line, make the cavity a two-deck cavity resonator. A channel slot is etched on the middle layer of the folded cavity to allow fields of both regions above and below the deck connected in one. In the folded case, we found that its electric field is strongest at the far side edges. So we remove the nearby vias without affecting its field distribution. The signal can still go through from lower cavity to upper one. Such that, the third design of this thesis is accomplished, which is based on the second circuit with removing the edge vias. This design reduces the circuit complexity and still preserves the circuit performance.