1、螺旋濾波器 主要特點 1.)頻率范圍：幾十MHz到到大約2GHz； 2.)帶寬：0.5%-超過50%; 3.)低損耗，相比同頻率范圍的LC分立元件濾波器具有低損耗的特點(螺旋諧振腔無載Q值能達到1000)； 4.)寬帶寬，相對一同頻率范圍的SAW、Crystal濾波器能實現更寬的帶寬；5.）小尺寸，相比于同頻率范圍的同軸腔濾波器尺寸小很多，例如，一個54MHz的諧振(Q=550)，同軸腔為4.5英尺0.7英寸，而螺旋濾波器為2英寸1.5英寸；6.）加工容易，適合大批量生產。 應用領域1.)衛星通信(1) (下圖為2個螺旋濾波器，能很好達到選擇性和群時延要求)(1).Reference：High

2、 Performance Helical Resonator FiltersBy Ming Yu and Van Dokas Microwave Conference, 2004. 34th European Publication Date: 13 Oct. 2004Volume: 2, On page(s): 989- 992 ISBN: 1-58053-992-0 圖. 2. 7-1 螺旋濾波器圖. 1. 8-2-2 螺旋濾波器2.)應用于雙工器(1)、多工器、倍頻器、變頻器、放大器、振蕩器(2)等電路單元。(1).Reference: R. Levy and K. Andersen “

3、An optimal low loss HF diplexer using helical resonators”, Microwave Symposium Digest, 1992., IEEE MTT-SInternational, 1-5 June 1992, Pages:1187 - 1190 vol.3(2).Reference: Everard, J.K.A.; Cheng, K.K.M.; Dallas, P.A.; “High-Q helical resonator for oscillators and filters in mobile communications sys

4、tems”, Electronics Letters ,Volume: 25 , Issue: 24 , 23 Nov. 1989 Pages:1648 1650圖. 3. 一個典型的螺旋濾波器產品不同結構的螺旋濾波器1. 雙模螺旋濾波器(1)(1).Reference:Kwok, R.S.; Fiedziuszko, S.J.; “Dual-mode helical resonators”, Microwave Theory and Techniques,IEEE Transactions on , Volume: 48 , Issue: 3 , March 2000 Pages:474 -

5、 477圖. 4. 雙模螺旋濾波器(helix: copper;core: Teflon ;Cavity:aluminum).圖. 5. 處理響應曲線(IR: 1.8dB;BW: 10MHz ;Qu:1400). 螺旋濾波器主要部件：螺旋諧振腔(見下圖)d = Mean helix diameter (cm)C = Inside diameter of circular shield (cm)S = Length of square shield side (cm)H = Height of shield (cm)f = Resonant frequency (MHz)Q = Unloaded

6、 Q of an air-filled resonatorQd = Unloaded Q of a dielectric-filled resonatorN = Number of turns on helixp = Helix pitch (turns/cm)Z0 = Characteristic impedance of air-filled helical transmission line ()Zd = Characteristic impedance of dielectric-filled helical transmission line ()g = Wire diameter

7、and also space between turns (cm)tan(d) = Loss tangent of dielectric material 螺旋諧振腔設計：1.)空氣填充2.)介質填充設計曲線螺旋諧振腔諧振頻率精確計算(1)圖.10.螺旋腔體結構1.)基模頻率f1：2.)二次模頻率f2：3.)三次模頻率f3：(1).Reference: Resonant frequencies of helical resonators by Antoniuk, J.; Zukocinski, M.; Abramowicz, A.; Gvvarek, W.; 不同的螺旋線圈形式(1)(1).R

8、eference: US Pat.NO 3936776 “Interspersed double winding helical resonator with connections to cavity” by John Robert Sundquist Feb 3, 1976優點：抑制奇次諧波，提供更好的腔體間的 耦合特性圖.11.Helical繞線形式圖.12.提高了奇次諧波的抑制擴展螺旋濾波器帶寬的途徑(1).Reference: US Pat.No. 4284966 Wide bandwidth helical resonator filterBy Wanat; Ronald J. (

9、Elgin, IL) August 18, 1981 圖.13.具體的腔體結構1.)縮短腔體距離(1)2.) 在耦合窗加介質(1)，如：alumina、polypropylene、 teflon等；圖.14.加介質后的螺旋濾波器圖.15.對應響應(1).Reference: US Pat.NO. 4365221 Helical resonator filter with dielectric apertures By Vizmuller; Peter (Thornhill, CA) December 21, 1982 3.)將螺旋線圈的開路端增大；4.)在耦合窗加U型耦合圈。參考文獻參考文獻1 Peter Vizmuller, “Filters with Helical and Folded Helical Res