本論文提出一操作於Ka頻帶之雙向向量合成式相移器(bi-directional vector sum phase shifter, BDVSPS),可用於相位陣列的架構來實現收發端的射頻電路。 本論文可以分成主動和被動部分,為了實現雙向架構,其中四相位產生器是由90度耦合器和0-π相位切換器來實現的,而且被動的四相位產生器本身亦可實現雙向功能。為了補償被動元件的損耗和精準地控制相位,本文採用兩個雙向可變增益放大器來實現,分別調整雙向放大器的偏壓來控制增益,再由功率合成器合成相位。反向操作時,訊號由功率整合器端進入,經由雙向可變增益放大器的反向路徑放大後,再用90°耦合器輸出,以此實現雙向向量合式相移器。 本文採用台積電0.18 μm CMOS製程實現,可達到等效4位元解析度,而量測結果均方根增益誤差為0.4 dB,RMS相位誤差小於0.4°,平均增益為-7.6 dB,直流功耗最大為20 mW。 關鍵字:相移器、向量合成式相移器、Ka頻帶、雙向可變增益放大器。
This thesis proposes a bi-directional Ka band vector sum phase shifter (BDVSPS) that can be used in phase array transceiver. This phase shifter uses a 90° coupler and a phase-invertible variable attenuator (PIVA) to generate orthogonal (in-phase and qudrature, IQ) signals, and bi-directional variable gain amplifiers (BDVGA) to synthesize vecter signal through appropriate bias, then it uses a power combiner to add I and Q signal to implement the bi-directional vecter sum phase shifter. When the phase shifter operates in the reverse direction, signal comes from power combiner, then goes toward the BDVGA in reverse direction, the output is at the 90° coupler. This circuit is implemented in TSMC 0.18μm CMOS process. It has 4-bit resolution. The measured RMS gain error is 0.4dB, and RMS phase error is less than 0.4°. The average gain is -7.6dB with maximum DC power consumption at 20mW. Keywords:phase shifter, vecter sum phase shifter, Ka band, bidirectional variable gain amplifier (BDVGA).