準光學雙光柵帶通濾波器的分析與製作

Abstract

本論文提出一雙光柵結構的光學帶通濾波器的設計. 兩種Ka頻帶和 W 頻 帶的濾波器被製作, 量測. 這兩種濾波器在頻率多工器中是用來分離基頻 所需的諧波頻率.首先, 我們用TEM 或傳輸線的等效電路模式來分析, 測 量結果與理論分析是一致的. 再者, 我們用頻域趨近法(SDA) 來分析層( layered)濾波器的結構, 這部份所探討的範圍含蓋了濾波器在製程上對不 準性 (mislignment),斜向入射TEM 波及介電常數的變化對濾波器的影響 等. A two-grid approach for quasioptical bandpass filter design is presented. Two bandpass filters for used in Ka band and W band, with an inductive grid and a capacitive slot on both sides of substrate, have been fabricated and measured. The filters are required in frequency multiplier arrays to provide the separation of the fundamental and desired harmonic. For the theoretical analysis of the two-grid bandpass filters, first the TEM or transmission-line model is used. Good agreement between the measured and computed results is obtained. Later, the widely-used spectral domain approach is employed to analyze the layered filter structure. Case studies investigated in this part include the misalignment arised in fabrication process, the filter characteristics for obliquely incident TEM waves, and the influence of the variation of dielectric constants on the filter response.