A new circuit topology for the design of a single balanced second‐order subharmonic mixer (SHM) is proposed. In the proposed topology, it is not necessary for the radio frequency (RF) and local oscillator (LO) signal to be within 15% frequency difference. Thus, the limitation of a conventional rat‐race mixer has been alleviated. Moreover, it shows very low conversion loss, high LO‐to‐RF, LO to intermediate frequency (IF), and 2LO‐to‐RF port isolations. The measured minimum down conversion loss is 5.8 dB at 13 GHz and remains below 7.65 dB over the 2 GHz RF operational band 12‐14 GHz for a fixed IF of 550 MHz. Measured LO‐to‐RF and LO‐to‐IF port isolations are better than −40 dB over the entire operational band. The 2LO‐to‐RF isolation is more than −62 dB which is extremely necessary for a second harmonic mixer where 2LO and RF frequency are close to each other. The input 1‐dB compression point is measured to be −1 dBm.

中文翻译：

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低转换损耗的单平衡次谐波混频器

提出了一种用于单平衡二阶次谐波混频器（SHM）设计的新电路拓扑。在提出的拓扑中，射频（RF）和本地振荡器（LO）信号的频率差不必在15％之内。因此，减轻了常规鼠混频器的局限性。此外，它显示出非常低的转换损耗，较高的LO-to-RF，LO至中频（IF）和2LO-RF端口隔离。在550 MHz的固定IF情况下，在13 GHz时测得的最小下变频损耗为5.8 dB，在2 GHz的12-14 GHz RF工作频带内仍保持在7.65 dB以下。在整个工作频段内，测得的LO-to-RF和LO-to-IF端口隔离度均优于−40 dB。2LO到RF的隔离度大于-62 dB，这对于2LO和RF频率彼此接近的二次谐波混频器非常必要。输入的1-dB压缩点测得为-1 dBm。