This letter presents a low-cost third-harmonic mixer suitable for ${W}$ -band retrodirective systems. Measured results show that when fixing the local oscillator (LO) frequency at 35 GHz, the conversion loss (CL) below 11 dB is achieved over the radio frequency (RF) range of 100–110 GHz with intermediate frequency (IF) from dc to 5 GHz, while for the RF range of 108 GHz, the minimum CL of 6.8 dB is obtained. Therefore, the presented mixer exhibits an excellent performance with low CL in comparison with that of a normal subharmonic mixer (SHM). The isolations of RF/LO and RF/IF are improved to the level of 35 and 38 dB, respectively. The simulated and measured isolations of LO/RF are 41 and 37 dB, respectively. This mixer has properties of low LO frequencies, high isolations, and low CL; therefore, it provides a high-performance and low-cost alternative solution for the applications of retrodirective systems.

中文翻译：

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用于波段反向系统应用的低成本三次谐波混频器

这封信介绍了一种低成本的三次谐波混频器，适用于 ${W}$ 波段逆向系统。测量结果表明，当将本地振荡器 (LO) 频率固定在 35 GHz 时，在 100–110 GHz 的射频 (RF) 范围内，中频 (IF) 从直流到5 GHz，而对于 108 GHz 的射频范围，获得了 6.8 dB 的最小 CL。因此，与普通的次谐波混频器 (SHM) 相比，所提出的混频器具有低 CL 的优异性能。RF/LO 和 RF/IF 的隔离度分别提高到 35 和 38 dB 的水平。LO/RF 的仿真和测量隔离度分别为 41 和 37 dB。该混频器具有本振频率低、隔离度高、CL低的特点；因此，它为逆向系统的应用提供了一种高性能、低成本的替代解决方案。