本論文研究使用基板合成波導(Substrate Integrated Waveguide)實現的三階濾波交叉器(Filtering Crossovers)，其基於雙模態共振腔的TE102以及TE201兩正交模態可以實現對雙通道的交叉傳輸，以及良好的隔離效果，且透過GCPW的耦合架構增加及控制耦合量達成較高的頻寬和保留良好的隔離度，配合1/8模SIW腔體和輸入/輸出饋線的位置分配得以使寬止帶的特性出現在比例頻寬較大的設計中。大多數相關研究中往往以限制頻寬的方式使止帶範圍增加。 第一個電路使用一個雙模態(TE102、TE201)全模腔體和四個主模態(TE101)1/8模腔體在腔體間的耦合窗口上配合GCPW耦合構造所組成，中心頻率同為3GHz，3dB比例頻寬同是9%，基於全模腔體雙模態互相正交的特性，訂定雙模態腔體的窗口位置於每邊中心位置，可以有控制比例頻寬和抑制高階的模態，且藉由1/8模腔體和輸入/輸出端口配合的電路特性，將零點靠近通帶，從而使較高頻寬下擁有良好的隔離度且寬止帶特性的微小化基板合成波導濾波交叉器得以實現。 第二個電路透過金屬通孔將雙模腔體進行干擾，使其雙模態其一往高頻偏移，另一則保持不變，使其保留最小設計面積且擁有更靈活的TE102/ TE201比率，得到一原頻率的通道且擁有另一較高頻通道。 第三個電路透過蝕刻金屬槽孔改變表面電流，藉此影響雙模腔體，相對於第二片電路使其TE102或TE201模態其一往低頻偏移，使其獲取更小設計面積和靈活的TE102 /TE201比率，得到一原頻率的通道且擁有另一較低頻通道。 ;This thesis investigates a third-order filtering crossover using substrate integrated waveguide (SIW), based on the resonance of the orthogonal TE201 and TE102 modes in the dual-mode cavity. The crossover enables cross transmission between two channels with acceptable isolation. The coupling structure utilizes coplanar waveguide for increased bandwidth and good isolation control. Various methods are employed to suppress unwanted modes, resulting in the appearance of wide stopbands in designs with larger fractional bandwidth. The first circuit consists of a full-mode (TE201, TE102) cavity and four 1/8-mode (TE101) cavities, with a 3 GHz center frequency and a 3 dB fractional bandwidth of 9%. The positioning of windows for the dual-mode cavities at the center of each side leverages the orthogonal nature of the dual-mode cavities to control the fractional bandwidth and suppress higher-order modes. The utilization of 1/8-mode and the feed characteristics at input/output ports reduce higher modes and bring transmission zeros which are closer to the passband, achieving high isolation and wide stopband characteristics in a compact SIW filter crossover. The second circuit introduces interference to the dual-mode cavities through metal vias, causing a frequency shift in either TE102 or TE201 modes towards higher frequencies. This allows for a single original frequency channel while having another higher frequency channel with minimal design area. The third circuit uses etched metal slots to interfere with the dual-mode cavities, causing a frequency shift in either TE102 or TE201 modes towards lower frequencies. This enables a single original frequency channel while having another lower frequency channel with a smaller design area and flexible TE102/TE201 ratio.
