Broadband multi-source excited meander embedding sector antenna for series superconducting Josephson junction THz mixer

Series Josephson junction (JJ) structure has been presented to enhance the impedance of a superconducting terahertz mixer to match the coupled antenna. And the impedance matching between a single antenna and low-impedance JJs embedded in the antenna has been a research hotspot recently. However, the reported antennas all work in resonant modes, resulting in a strict requirement for the positions and the number of the JJs in series. In this paper, we propose a meander embedding sector antenna operated in a traveling-wave mode for series JJs. Multi-source excitation in an antenna is applied to the numerical simulation. The experiment shows that up to seven JJs in series have been successfully inserted into the antenna, and the antenna still maintains good performance. Furthermore, up to 48 % of the 10-dB relative bandwidth of this antenna is achieved, which has a great advantage for wideband superconducting series JJ devices.