Complex magnetically insulated transmission line oscillator (MILO), as an important development direction, can enhance the power efficiency and generate dual-band high power microwaves (HPMs). A complex MILO and a preliminary dual-band radiation system have been proposed in our previous studies. However, the axial length of the dual-band radiation system is too long to meet the compact requirements. In this paper, a compact dual-band radiation system is presented and investigated numerically. The compact dual-band radiation system comprises a dual-band cross-shaped mode converter and a dual-band coaxial conical horn antenna. It can convert two coaxial TEM mode microwaves (1.717 GHz and 4.167 GHz) generated by the complex MILO into the coaxial TE₁₁ mode microwaves, and then radiate them into the air. At 1.717 GHz, the gain of the antenna is 17.9 dB, and the total return loss and diffraction loss are 1.50% and 0, respectively. At 4.167 GHz, the gain is 19.4 dB, and the total return loss and diffraction loss are 1.17% and 0.78%, respectively. The power handling capacity of the antenna is 5.1 GW at 1.717 GHz and 2.0 GW at 4.167 GHz. Comparing with the original structure, the length of the dual-band radiation system is reduced by 45.2%.

复合磁绝缘传输线振荡器（MILO）作为一个重要的发展方向，可以提高功率效率并产生双频高功率微波（HPM）。在我们之前的研究中已经提出了一个复杂的 MILO 和一个初步的双波段辐射系统。但双频辐射系统的轴向长度过长，无法满足紧凑的要求。在本文中，提出了一种紧凑的双波段辐射系统并对其进行了数值研究。紧凑型双频辐射系统包括双频十字型模式转换器和双频同轴锥形喇叭天线。它可以将复合 MILO 产生的两个同轴 TEM 模式微波（1.717 GHz 和 4.167 GHz）转换成同轴 TE ₁₁模式微波，然后将它们辐射到空气中。在 1.717 GHz 时，天线增益为 17.9 dB，总回波损耗和绕射损耗分别为 1.50% 和 0。在 4.167 GHz 时，增益为 19.4 dB，总回波损耗和衍射损耗分别为 1.17% 和 0.78%。天线的功率处理能力在 1.717 GHz 时为 5.1 GW，在 4.167 GHz 时为 2.0 GW。与原结构相比，双频辐射系统的长度减少了45.2%。