A novel balanced BPF using the folded half-mode substrate integrated waveguide has a central frequency of 4.65 GHz with 0.55 GHz BW and in-band insertion loss of 2.2 dB. The size of an FHMSIW is about 1/4 of the substrate integrated waveguide (SIW). The common-mode rejection levels are greater than 40 dB over a wide frequency range.

1.本專利案以微帶線饋入能量至摺疊式基板合成半模波導結構，以此結構為基礎，設計一款具共模壓制效果之平衡式帶通濾波電路，中心頻率為4.65 GHz，頻寬0.55 GHz，損耗2.2 dB。
2.微帶線饋摺疊式基板合成之半模波導結構，此為同類型結構之濾波器首創，電路尺寸為基板合成波導結構的1/4，電路Q值遠大一般常用之平面傳輸線電路（如微帶線），而電路之共模壓制效果超過40 dB，其特性優於其他結構之平衡式帶通濾波電路。
3.濾波器結構能移轉至其他頻段與不同頻寬要求的濾波器設計上，具有普遍性與便利性。
4.本專利案的構想尚未見諸其他人所發表之文獻上，目前中華民國專利公報內，也還找不類似結構之帶通濾波器濾的資料。
5.需要無線通訊或是無線傳送與接收的場合越來越多，未來市場可期。

The folded substrate integrated waveguide balanced BPF has advantages of EMC immunity property, wide BW, wide stopband, good CMRR, and good signal selectivity. It can be used as a RF front-end filter component of a wireless communication system, such as wifi and WLAN systems, and cellar phone base station.