A Terahertz Broad Compound Tuning Range Extended Interaction Oscillator Operating at Quasi-TM51 Mode

A terahertz (THz) broad compound tuning range extended interaction oscillator (EIO) operating at quasi-TM51 mode is proposed in this article. Based on the eigenmode analysis, the quasi-TM51 mode has a higher characteristic impedance R/O than the TM51 mode. Meanwhile, it can help to address the compatible mode competition issue brought on by increasing the gap number of traditional EIO devices, suiting to further power improvement. Moreover, it can work effectively and stably in multiple modes, so it can achieve a wider continuous tuning range. The results of particle-in-cell (PIC) simulation show that driven by a 28.3-kV and 25-mA electron beam, the novel quasi-TM51 mode EIO can generate a power of 2601 mW at 612.15 GHz and achieve a 3-dB bandwidth of 1.2 GHz. By tuning the beam voltage between 25.0 and 31.0 kV, the EIO source can produce more than 64-mW THz signals covering 607.21-616.29 GHz. In addition, by compound tuning, the frequency tuning range has been increased from 9.08 to 11.98 GHz. Also, the proposed EIO can produce more than 368-mW THz signals covering 607.07-619.05 GHz.