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幅度校準(zhǔn)功能的低附加相移數(shù)控衰減器
2023年電子技術(shù)應(yīng)用第2期
李想
中國西南電子技術(shù)研究所,, 四川 成都 610036
摘要: 提出了一種可用于Ka 波段相控陣系統(tǒng)的高精度低附加相移五位數(shù)控衰減器(Digital Controlled Attenuator,DCA),。該DCA采用了嵌入式開關(guān)的T型,、簡化T型和Π型三種衰減結(jié)構(gòu)設(shè)計(jì)基本衰減單元,,實(shí)現(xiàn)了15.5 dB的衰減動(dòng)態(tài)范圍和0.5 dB的最小衰減步進(jìn)。幅度校準(zhǔn)技術(shù)被用于信號通路中,,可有效降低由工藝波動(dòng)引起的衰減幅度誤差增大問題,,增強(qiáng)了電路設(shè)計(jì)的魯棒性。同時(shí),,在T型和Π型衰減結(jié)構(gòu)中采用電容補(bǔ)償技術(shù)提高其高頻衰減性能,,實(shí)現(xiàn)低附加相移?;?5 nm CMOS工藝,,對所提出的DCA進(jìn)行了優(yōu)化仿真、流片與測試驗(yàn)證,。芯片核心尺寸為500 µm×150 µm,。測試結(jié)果表明:在25~35 GHz頻帶范圍內(nèi),參考態(tài)插入損耗為6.54~8.6 dB,,32衰減態(tài)對應(yīng)的輸入/輸出回波損耗優(yōu)于-15 dB,,幅度誤差RMS和相位誤差RMS分別為0.12~0.26 dB和1.02°~2.07°。
中圖分類號:TN402
文獻(xiàn)標(biāo)志碼:A
DOI: 10.16157/j.issn.0258-7998.222955
中文引用格式: 李想. 幅度校準(zhǔn)功能的低附加相移數(shù)控衰減器[J]. 電子技術(shù)應(yīng)用,,2023,,49(2):26-31.
英文引用格式: Li Xiang. Low phase variation digital controlled attenuator with amplitude calibration function[J]. Application of Electronic Technique,,2023,49(2):26-31.
Low phase variation digital controlled attenuator with amplitude calibration function
Li Xiang
Southwest China Institute of Electronic Technology,,Chengdu 610036,,China
Abstract: This paper presents a high accuracy and low phase variation 5-bit digital controlled attenuator (DCA) for Ka-band phased-array system applications. The DCA adopts three attenuation topologies of T-type, simplified T-type and Π-type topologies with embedded switches to design the basic attenuation cells, and realizes the attenuation dynamic range of 15.5 dB and the minimum attenuation step of 0.5 dB. Amplitude calibration technology is used in signal path, which can effectively reduce the increase of attenuation amplitude error caused by process fluctuation and enhance the robustness of circuit design. At the same time, capacitance compensation technology is used in T-type and Π-type attenuation topologies to improve their high-frequency attenuation performance and achieve low phase variation. Based on 65 nm CMOS process, the proposed DCA is optimization simulated, taped out, measured and verified. The core area of the chip is 500 µm×150 µm. The measurement results show that within frequency range of 25~35 GHz, the insertion loss of reference state is 6.54~8.6 dB, the input/output return loss corresponding to 32 attenuation states is better than -15 dB, and the amplitude error RMS and phase error RMS are 0.12~0.26 dB and 1.02~2.07o, respectively.
Key words : digital controlled attenuator;amplitude calibration,;low amplitude error,;low phase variation

0 引言

    目前,相控陣系統(tǒng)被廣泛應(yīng)用于雷達(dá),、衛(wèi)星通信以及遙測等領(lǐng)域,。為了實(shí)現(xiàn)高速鏈路、靈活的信號覆蓋和抗干擾能力的結(jié)合,,需要大量高性能的相控陣發(fā)射/接收(Transmit/Receive,,T/R)前端模塊[1-2]。在相控陣T/R的每個(gè)單元中,,幅度控制單元用于補(bǔ)償單元之間的增益變化從而實(shí)現(xiàn)天線波束旁瓣水平(Side Lobe Level, SLL)的降低[3],。為了實(shí)現(xiàn)SLL和波束零點(diǎn)的精確調(diào)整,需要高精度,、大帶寬及小步進(jìn)的幅度控制電路[4],。

    衰減器和可變增益放大器[5](Variable-Gain Amplifiers,VGA)是實(shí)現(xiàn)幅度控制功能的兩種重要器件,。相比于VGA,,衰減器具有高線性度、大帶寬,、大衰減范圍,、低幅度誤差/附加相移以及零功耗等優(yōu)勢,更適合于微波毫米波頻段相控陣系統(tǒng)應(yīng)用,。圖1所示為廣泛采用的幾種典型衰減器拓?fù)浣Y(jié)構(gòu),。分布式衰減器能提供較寬的帶寬和較低的插入損耗,但其占用電路面積較大且一般只能實(shí)現(xiàn)小于10~15 dB的衰減范圍[6-7],。開關(guān)選通式衰減器能實(shí)現(xiàn)較低的幅度/相位誤差,,但由于大量的串聯(lián)開關(guān)造成損耗較大[8-9]。開關(guān)嵌入式T/Π型衰減器具有較低的損耗,、大衰減范圍以及面積小等優(yōu)點(diǎn),,滿足大規(guī)模相控陣T/R應(yīng)用[10-13]。然而,,開關(guān)嵌入式T/Π型衰減器依然存在著一些技術(shù)難點(diǎn):(1)多級衰減單元級聯(lián)時(shí),,由于衰減單元對負(fù)載阻抗比較敏感以及工藝波動(dòng)和高低溫變化,造成衰減幅度精確性降低;(2)不同衰減狀態(tài)時(shí)的附加相移變化較大,,需特別補(bǔ)償,;(3)由于晶體管和電路互聯(lián)布線的寄生電容影響,高頻(毫米波頻段)應(yīng)用受到限制,。




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作者信息:

李想

(中國西南電子技術(shù)研究所,, 四川 成都  610036)




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