Two W-band CMOS elliptical baluns (i.e. balun-1 and balun-2) for 94 GHz image radar, and one miniature Ka-band CMOS square balun (i.e. balun-3) with short-terminal and input capacitor (for elimination of the inductive imaginary part of the input impedance at the input port) for 28 GHz 5G communication system are demonstrated. These baluns are applicable to a down-conversion mixer for conversion of the single RF and LO input signals to differential signals. They are also applicable to a phase shifter for conversion of the single I and Q signals (from the quadrature coupler) to differential I (i.e. I + and I −) and Q (i.e. Q + and Q −) signals. Instead of the traditional balun structure that uses three sections of thin M₅ (or M₈) interconnection lines (underneath the thick top M₆ (or top M₉) main structure), the proposed balun structures use only one section of thin M₅ (or M₈) interconnection line to enhance S₂₁ and S₃₁. Balun-2 (with M₉ main structure thickness of 3.4 μm) attains S₂₁ of − 4.98 to − 4.57 dB, S₃₁ of − 4.85 to − 4.59 dB, amplitude imbalance magnitude (AIM) smaller than 0.15 dB and phase difference deviation (PDD) smaller than 4° for 90–100 GHz. Balun-3 (with M₆ main structure thickness of 2.34 μm) occupies a small chip area of 0.042 mm², and achieves S₂₁ of − 4.97 to − 4.44 dB, S₃₁ of − 4.68 to − 4.29 dB, AIM smaller than 0.28 dB and PDD smaller than 2.3° for 27–29 GHz. The prominent results of these baluns indicate that they are suitable for W-band and Ka-band systems.

两个用于94 GHz图像雷达的W波段CMOS椭圆巴伦（即balun-1和balun-2），以及一个带有短端子和输入电容器的小型Ka波段CMOS方巴伦（即balun-3）（用于消除说明了28 GHz 5G通信系统的输入阻抗（输入端口的输入阻抗的感性虚部）。这些巴伦适用于下变频混频器，用于将单个RF和LO输入信号转换为差分信号。它们也适用于移相器，用于将单个I和Q信号（来自正交耦合器）转换为差分I（即I +和I-）和Q（即Q +和Q-）信号。代替使用三段细M ₅（或M ₈）互连线（在粗顶部M下）的传统巴伦结构_在图6（或顶部M _9的主要结构）中，提出的平衡-不平衡变换器结构仅使用细的M ₅（或M ₈）互连线的一部分来增强S ₂₁和S ₃₁。Balun-2（M ₉主结构厚度为3.4μm）的S ₂₁为-4.98至-4.57 dB，S ₃₁为-4.85至-4.59 dB，振幅不平衡量（AIM）小于0.15 dB，相位差偏差（对于90–100 GHz，PDD）小于4°。Balun-3（M ₆主结构厚度为2.34μm）占用0.042 mm ²的小切屑面积，并且使S ₂₁为-4.97至-4.44 dB，S ₃₁在27–29 GHz频率范围内为-4.68至-4.29 dB，AIM小于0.28 dB，PDD小于2.3°。这些不平衡变压器的突出结果表明它们适用于W波段和Ka波段系统。