| 摘要: | 本論文以被動積體電路微小化為目標，且以縮小尺寸同時不減損頻寬為設計主軸，因微波電路往往應用特定電氣長度為基本組件，是造成主、被動電路面積過大的主因；傳統縮小傳輸線方式會以集總元件等效T型或π型電路，但此等效僅於單一頻率成立，造成縮小面積後頻寬亦隨之減損。本研究以橋式T線圈，替代傳統T模型，將使用頻率範圍大幅提升，且同時達到微小化目的。電路實現上，使用平衡式電感與平行板電容，於砷化鎵(GaAs)與玻璃積體被動(GIPD)製程中實現，並應用於微型化寬頻四路威爾京生分波器、超寬頻多模態帶通濾波器與波束成型網路。首先，以玻璃積體製程實現寬頻四路威爾京生分波器，中心頻率1.6 GHz，通帶內介入損耗最小值1.135 dB，以反射損耗大於20 dB定義頻寬可達117%，相位差0.269°，中心頻率下之尺寸僅為0.0245×0.0245 λ02。其次，將橋式T線圈的寬頻特性應用於超寬頻多模態帶通濾波器，其中以砷化鎵積體製程實現三模態帶通濾波器，中心頻率6.85 GHz，以反射損耗大於20 dB定義，頻寬為86.6%，通帶內介入損耗最小值0.895 dB，尺寸為0.02×0.02 λ02；以玻璃積體製程實現者，中心頻率6.85 GHz，以反射損耗大於15 dB定義，頻寬為89%，最小介入損耗0.534 dB，電路尺寸為0.0376×0.0292 λ02；又為了增加通帶選擇度，以玻璃積體製程實現五模態帶通濾波器，中心頻率6.85 GHz，以反射損耗大於10 dB定義頻寬為96.6%，最小介入損耗1.327 dB，中心頻率下之尺寸僅為0.0548×0.0351 λ02。最後，結合巴特勒矩陣與單刀四擲(SP4T)開關成波束成型網路，提供陣列天線調整輻射場型使用，電路以玻璃積體製程實現，中心頻率2.4 GHz，量測之介入損耗為-12.13±1.605dB (±45°path)與12.25±1.12dB (±135°path)，相位誤差-6.7°~-0.3°(±45°path)與2.5°~11.3°(±135°path)，以反射損耗大於15 dB定義頻寬為16.6%，功率消耗4.5 mW，中心頻率下尺寸為0.0368×0.0368 λ02。綜合以上電路皆遠小於傳統設計，且相較於理想傳輸線設計方式並無頻寬減損，證實橋式T線圈架構的確能對被動電路面積有大幅度的尺寸縮減，並不減損效能。In this thesis, very compact integrated passive circuits with high performance are presented. The major bottleneck of the size reduction of active and passive microwave circuits is the requirement of multiple transmission lines with given electrical length. Traditionally, lump elements are used to replace the transmission line, e.g. the equivalent T or π model. Although the size can be reduced, the bandwidth of the resulted microwave circuit is also reduced. This is due to the fact that those lumped T or π networks are equivalent to transmission line at single frequency only. In this work, the bridged T-coil is used to replace the conventional T model, such that the advantages of compact size and wide frequency bandwidth can both be achieved. The bridged T-coil can be implemented using balance inductor and metal-insulator-metal (MIM) capacitor in GaAs semiconductor IC process or Glass Integrated Passive Device (GIPD) process to achieve very compact size. It is then applied to the design of wideband four-way Wilkinson power divider, ultra-wideband multimode resonator Bandpass filter, and a switch beamforming network. First of all, the proposed wideband four-way Wilkinson power divider is fabricated in GIPD process with a circuit size of 0.0245λ0 × 0.0245λ0 at 1.6 GHz. The measured minimum insertion loss is 1.18 dB, the fractional bandwidth is 117% with a return loss of greater than 20 dB, and the phase error is less than 0.269°. Then, by implementing the stepped-impedance resonator using the proposed bridged T-coil structure, several novel wideband multimode resonator Bandpass filters for ultra-wideband application are proposed. Specifically, the proposed triple-mode Bandpass filter fabricated in GaAs has a circuit size of only 0.0376λ0 × 0.0292λ0 at 6.85 GHz, a minimum insertion loss of 0.895 dB and a bandwidth of 86.6% for a return loss of greater than 10 dB. Another triple-mode Bandpass filter in GIPD process exhibits a circuits size of 0.02λ0 × 0.02λ0 at 6.85 GHz, a minimum insertion loss of 0.644 dB, and a fractional bandwidth of 89% for a return loss of greater than 15 dB. In order to improve the selectivity, a five-mode Bandpass filter is also designed using the GIPD process. Its circuit size is 0.0548λ0 × 0.0351λ0 at 6.85 GHz, the minimum insertion loss is 1.327 dB, and the fractional bandwidth is 96.6% for a return loss of greater than 10 dB. Finally, a compact GIPD beamforming network including a 4×4 Butler matrix and a SP4T switch is demonstrated, and the circuit size is only 0.037λ0 × 0.037λ0 at the center frequency of 2.4 GHz. The measured insertion losses are within -12.13±1.605dB (±45°path) and -12.25±1.12dB(±135°path), phase error are -6.7°~-0.3°(±45°path) and 2.5°~11.3°(±135°path), and the DC power consumption is 4.5 mW.Compared with conventional designs, the above circuits are smaller in size with no bandwidth reduction as compared with their transmission-line based counterparts. The effectiveness of bridged T-coil on the design of miniaturized on-chip passive microwave circuit is also validated through proposed design examples. |
