單平面式W頻段混波器與倍頻器

Abstract

摘要 本報告提出一些使用於W頻段的混頻電路與倍頻電路，W頻段的混頻器依所使用的180度混成器(180o hybrid coupler)的不同分為三種，其一為使用全由有限寬地面共平面波導為結構的岔路環耦合器(rat-race ring coupler)所製成的混波器，其轉頻耗損在75到95 GHz頻率範圍內平均約為11dB，其二為使用有限寬地面共平面波導轉換為共平面帶線結構的岔路環耦合器所製成的混波器，其轉頻耗損在75到95 GHz之間平均約為16dB；其三為使用有限寬地面共平面波導為結構的超寬頻岔路環耦合器，主要是利用一個將共平面波導的訊號與地線作扭轉所製成的相反器來代替岔路環的四分之三波長線段來達到寬頻效果，用此耦合器製成的混頻電路在沒有偏壓的狀況之下於20到100GHz之間約有平均10dB的轉頻耗損，加偏壓之後則有平均11dB的轉頻耗損，且最低可達8dB的損耗。若將此超寬頻耦合器應用在次諧波混頻器上，則在55到98GHz之間有平均15 dB的轉頻損耗。W頻段倍頻器則使用兩個反相二極體加上一寬頻的平衡製非平衡端轉換器(balun)電路來製作，其轉頻耗損在W頻段75GHz~95GHz之間平均約為17dB且頻率響應十分平坦。此外，本報告也描述混頻器與倍頻器所使用的一些電路，包括180度相位產生器與直流阻絕電路的設計原理與方法。其量測結果也會在報告中描述。

Abstract This thesis presents some mixer and doubler circuits which is applied in the W-band. According to the coupler used in the mixers, we fabricate three types of mixer. First type is the finite ground coplanar waveguide (FCPW) rat-race ring mixer. The conversion loss of this mixer is around 12dB in 75GHz to 95GHz frequency range. Second type is the finite ground coplanar waveguide to coplanar strip(FCPW-CPS) rat-race ring mixer. The conversion loss of this mixer is around 16 dB from 75 GHz to 95 GHz. Third type is the broadband magic-T mixer. The magic-T coupler is fabricated in FCPW structure and applies a twist-line phase inverter to replace the half-wave-length phase inverter of the conventional rat-race ring in order to get broadband response. This type of mixer can get 11 dB conversion loss from 20GHz to 100GHz without DC-bias. If the DC voltage is applied on the diodes, this mixer can get typically 12dB conversion loss (minimum value is 8dB) from 75GHz to 100GHz. W-band frequency doubler comprises 2 anti-parallel Schottky diodes and an ultra-broadband CPW to CPS balun. The conversion loss of this doubler is around 17dB from 75GHz to 95GHz with flat frequency response. This thesis also describes the circuit design theory of the 180o coupler, balun, and DC-blocking circuits. The measured results will be shown in the following sections.