面向超表面天線設(shè)計(jì)的95～105 GHz SiGe BiCMOS寬帶數(shù)控衰減器

羅將; 張文柱; 程強(qiáng)

doi:10.11999/JEIT240059

面向超表面天線設(shè)計(jì)的95～105 GHz SiGe BiCMOS寬帶數(shù)控衰減器

doi: 10.11999/JEIT240059 cstr: 32379.14.JEIT240059

羅將^{1, 2, ,},
張文柱¹,
程強(qiáng)²

1.
杭州電子科技大學(xué)電子信息學(xué)院杭州 310018
2.
東南大學(xué)毫米波國(guó)家重點(diǎn)實(shí)驗(yàn)室南京 210096

基金項(xiàng)目: 國(guó)家重點(diǎn)研發(fā)計(jì)劃(2023YFB3811503)，浙江省自然科學(xué)基金(LQ23F040009)，毫米波國(guó)家重點(diǎn)實(shí)驗(yàn)室(K202316)

詳細(xì)信息

作者簡(jiǎn)介:
羅將：男，副教授，研究方向?yàn)橹悄艹砻嬲{(diào)控器件與芯片、毫米波單片集成電路與系統(tǒng)

張文柱：男，碩士生，研究方向?yàn)楣杌撩撞ǚ瓤刂齐娐吩O(shè)計(jì)

程強(qiáng)：男，教授，研究方向?yàn)槿斯る姶挪牧?、天線、微波毫米波成像、射頻電路、雷達(dá)系統(tǒng)

通訊作者:
羅將　luojiang@hdu.edu.cn

中圖分類號(hào): TN433
計(jì)量
- 文章訪問(wèn)數(shù): 414
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- 被引次數(shù): 0
出版歷程
- 收稿日期: 2024-01-26
- 修回日期: 2024-09-05
- 網(wǎng)絡(luò)出版日期: 2024-09-10
- 刊出日期: 2025-02-28

Design of 95～105 GHz SiGe BiCMOS Wideband Digitally Controlled Attenuator for Metasurface Antenna

1.
School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
2.
State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China

Funds: The National Key Research and Development Program of China (2023YFB3811503), Zhejiang Provincial Natural Science Foundation of China (LQ23F040009), The State Key Laboratory of Millimeter Waves (K202316)

摘要

摘要: 近年來(lái)，因?qū)﹄姶挪ň邆潇`活的調(diào)控能力，超表面天線技術(shù)受到來(lái)自通信、雷達(dá)以及天線領(lǐng)域?qū)W者的廣泛關(guān)注。其中，超表面天線單元中所使用的有源調(diào)控器件，是決定整個(gè)系統(tǒng)性能的最關(guān)鍵部件之一。該文基于0.13 μm SiGe BiCMOS工藝設(shè)計(jì)了一個(gè)95～105 GHz的五位寬帶數(shù)控衰減器芯片。該衰減器采用了反射式和簡(jiǎn)化T型兩種拓?fù)浣Y(jié)構(gòu)，其中4 dB與8 dB反射式衰減單元采用交叉耦合寬帶耦合器代替?zhèn)鹘y(tǒng)的3 dB耦合器或定向耦合器，同時(shí)獲得了高衰減精度和低插入損耗；而0.5 dB, 1 dB, 2 dB三個(gè)衰減單元均采用簡(jiǎn)化T型結(jié)構(gòu)。此外，利用RC正斜率和負(fù)斜率校正網(wǎng)絡(luò)分別應(yīng)用于不同的衰減單元進(jìn)行相位補(bǔ)償，極大地改善了衰減器的附加相移。經(jīng)過(guò)仿真驗(yàn)證，在95～105 GHz的感興趣工作頻率內(nèi)，衰減器芯片在0.12 mm²的緊湊的尺寸下實(shí)現(xiàn)了0～15.5 dB的衰減范圍，步進(jìn)為0.5 dB，基態(tài)插入損耗小于2.5 dB，幅度均方根誤差小于0.31 dB，附加相移均方根誤差小于2.2o。所提出的W波段衰減器可作為一個(gè)關(guān)鍵部件賦能集成T/R的輻散一體化超表面天線系統(tǒng)的硬件實(shí)現(xiàn)。
- SiGe BiCMOS /
- W波段 /
- 衰減器 /
- 交叉耦合寬帶耦合器 /
- 超表面
Abstract: Objective The W-band spectrum, spanning from 75 to 110 GHz, offers valuable spectrum resources, making it well-suited for high-speed wireless communication, radar detection, and biomedical imaging. Its lower atmospheric attenuation, compared to the commonly used 60 GHz band, further enhances its suitability for these applications. As modern wireless devices and electronic systems operate in increasingly complex electromagnetic environments, the demands on antenna systems are growing. These systems must independently control both radiated and scattered electromagnetic waves. Active phased array antennas, which integrate numerous transmit/receive (T/R) modules, provide precise control over the amplitude and phase of radiation elements, enabling superior manipulation of the radiated electromagnetic field. Meanwhile, rapidly advancing intelligent metasurface technology allows programmable, real-time modulation of scattered electromagnetic wave characteristics such as amplitude, phase, frequency, and polarization. This technology has attracted significant interest in the fields of communications, radar, and antenna systems. Consequently, metasurface antennas with active T/R modules offers a novel technological approach for efficient beam control of both radiated and scattered electromagnetic fields, providing new insights into solving complex electromagnetic environment problems. Digitally controlled attenuators (DSAs) are essential in metasurface antenna array systems, serving as millimeter-wave signal amplitude control modules. They primarily compensate for amplitude errors introduced by phase shifters or other components while also suppressing sidelobe levels in array antennas to enhance beam directivity. Additionally, these attenuators must exhibit minimal phase variation to reduce tracking errors, thus simplifying the calibration process. However, existing commercial millimeter-wave amplitude control chips are expensive and may face export restrictions, emphasizing the urgent need for high-performance, low-cost solutions to support the hardware implementation of metasurface antennas. Methods A 95 to 105 GHz DSA with 5-bit resolution is proposed. To address the issues of high insertion loss (IL), poor accuracy, and limited bandwidth in the large attenuation unit at W-band, a reflective structure based on a cross-coupled broadband coupler is proposed. The proposed coupler features a 180° inverter core and quasi-parallel stripline connections on both sides. At millimeter-wave frequencies (e.g., W-band), coupling capacitance introduced by the gaps creates a series resonance condition, achieving lower transmission loss and ensuring wide operational bandwidth. The 4 dB and 8 dB attenuation units, built using this structure, achieve high accuracy and low IL within a compact area. To minimize impedance mismatch during state switching, the attenuation units are cascaded in an order that reduces variations in amplitude and phase. Specifically, the 4 dB and 8 dB units are placed at the two ends of the attenuator to limit mutual interference. Smaller attenuation units (0.5 dB, 1 dB, and 2 dB) adopt a simplified T-type structure. The 0.5 dB unit, being more sensitive to impedance changes, is strategically positioned between the 1 dB and 2 dB units. Furthermore, phase changes during state switching are mitigated through a combination of positive- and negative-slope phase compensation networks. A positive-slope network is applied to the 4 dB unit, while negative-slope networks are used for the 0.5 dB, 1 dB, and 8 dB units. This dual compensation approach effectively avoids overcompensation, ensuring consistent amplitude and phase performance across all states, significantly improving the attenuator’s root means square (RMS) phase errors. Results and Discussions The layout of the proposed wideband DSA is shown in Fig. 10; the whole chip occupies a silicon area of 840 μm × 430 μm including all testing pads with a small core size of only 610 μm × 200 μm. It has five attenuation cells providing independent control of binary-coded attenuation levels of 0.5, 1, 2, 4, and 8 dB with a total of 32 states. Fig. 11 shows the simulated attenuation levels relative to the reference state for all 31 attenuation states within the desired frequency range of 95～105 GHz. The DSA achieves a dynamic attenuation range of 15.5 dB with a step resolution of 0.5 dB. The frequency response curves of adjacent states are evenly spaced with no overlap, indicating that the attenuator delivers precise amplitude control characteristics. The maximum phase variation relative to the reference state across all 31 attenuation states is less than 4.8°, as plotted in Fig. 12. As shown in Fig. 13, the IL in the reference state is less than 2.5 dB across the entire frequency band of interest. Fig. 14 illustrates the simulated RMS amplitude error and phase error versus frequency. The RMS amplitude errors remain below 0.31 dB over 95～105 GHz, while the RMS phase error is better than 2.2°. Table 3 summarizes the performance of the designed W-band attenuator and compares it with recently reported millimeter-wave DSAs. Compared to other attenuators, the proposed DSA demonstrates superior overall competitiveness, achieving low IL, high attenuation accuracy, and low RMS phase error within a compact chip size. While [6] achieves the lowest RMS phase error, it suffers from a high IL of 11.2 dB. In contrast, [20] offers excellent IL performance but is limited to a small attenuation range of only 4.7 dB. Conclusions In conclusion, the 5-bit W-band DSA presented in this paper, implemented in a 0.13 ${\text{μm}} $ SiGe BiCMOS process, offers an efficient and compact solution for wideband attenuation with low IL and minimal phase shift. The design integrates reflective and simplified T-type topologies, along with RC-based positive and negative slope correction networks applied to different attenuation units, enabling precise attenuation steps and optimized phase errors. The attenuator achieves an attenuation range of 0～15.5 dB with 0.5 dB steps over the 95～105 GHz frequency range, occupying a compact area of 0.12 mm². Simulated results show an IL of less than 2.5 dB, RMS amplitude error below 0.25 dB, and RMS phase error under 2.2°. The proposed DSA can serve as a key component empowering the hardware implementation of an integrated T/R metasurface antenna system with simultaneous radiation and scattering control.
- SiGe BiCMOS /
- W-band /
- Attenuator /
- Wideband coupler with cross-coupling /
- Metasurface

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圖 1 反射式衰減單元的拓?fù)浣Y(jié)構(gòu)圖

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圖 2 衰減量與歸一化負(fù)載阻抗的關(guān)系

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圖 3 所提出的耦合器的3維物理模型

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圖 4 耦合器在端口匹配時(shí)與傳統(tǒng)傳輸線的插入損耗仿真結(jié)果

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圖 5 等效電路模型

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圖 6 等效電路模型和3維物理模型仿真結(jié)果對(duì)比

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圖 7 相位補(bǔ)償結(jié)構(gòu)

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圖 8 不同相位補(bǔ)償結(jié)構(gòu)下阻抗的相位和模值隨頻率變化的響應(yīng)曲線

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圖 9 W波段5位數(shù)控衰減器原理圖

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圖 10 W波段5位數(shù)控衰減器版圖

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圖 11 全態(tài)衰減曲線

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圖 12 所有衰減態(tài)下相位變化曲線

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圖 13 插入損耗變化曲線

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圖 14 RMSA與RMSP曲線

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表 1 等效電路模型元器件的參數(shù)值

器件	參數(shù)值	器件	參數(shù)值
L₁	85.3 pH	C₁	0.5 fF
L₂	22.0 pH	C₂	2.7 fF
L₃	13.0 pH	C₃	12.8 fF
R₁	1.9 Ω	C₄	0.7 fF
k	0.7

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表 2 關(guān)鍵器件參數(shù)

器件	參數(shù)值	器件	參數(shù)值	器件	參數(shù)值	器件	參數(shù)值
T_1,2(W/L)	120 nm/630 nm	C_1,2,4	20 fF	R₄	1298 Ω	R₉	81 Ω
T₃(W/L)	120 nm/1050 nm	C₃	12 fF	R₅	57 Ω	R₁₀	223 Ω
T₄(W/L)	120 nm/850 nm	R₁	126 Ω	R₆	2273 Ω
T₅(W/L)	120 nm/900 nm	R₂	301 Ω	R₇	190 Ω
T_6,7(W/L)	120 nm/1200 nm	R₃	1433 Ω	R₈	100 Ω
W：發(fā)射極寬度；L：發(fā)射極長(zhǎng)度

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表 3 性能總結(jié)和已報(bào)道的硅基毫米波衰減器芯片對(duì)比

文獻(xiàn)	2014^[6]	2012^[18]	2018^[21]	2022^[20]	^#本文
工藝	65 nm CMOS	180 nm SiGe BiCMOS	65 nm CMOS	130 nm SiGe BiCMOS	130 nm SiGe BiCMOS
頻率(GHz)	50～110	57～64	80～110	190～220	95～105
拓?fù)浣Y(jié)構(gòu)	Distributed	Distributed	Coupled	Coupled lines	Reflected+T type
位數(shù)(bit)/步進(jìn)(dB)	14/0.75	4/1.0	6/NA	4/0.35	5/0.50
衰減范圍(dB)	0～10.0	0～11.8	0～14.5	0～4.7	0～15.5
插入損耗(dB)	11.2	11.0	4.5*	2.0	2.5
幅度均方根誤差(RMSA)(dB)	NA	＜1.54	＜0.31	＜0.34	＜0.31
相位變化(o)	＜5.0	12.0*	＜12.0	NA	＜4.8
相位均方根誤差(RMSP)(o)	＜1.4	＜3.6	NA	NA	＜2.2
面積(mm²)	0.38	0.94	0.06	0.03	0.12
*：估算；^#：仿真結(jié)果

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