Design and Cold Test of Dual Beam Azimuthal Supported Angular Log-Periodic Strip-Line Slow Wave Structure

A novel Ka-band azimuthal supported angular log-periodic strip-line (ASALS) slow wave structure (SWS) is proposed for a miniature radial sheet beam traveling wave tube (TWT). In the proposed SWS, two dielectric rods are employed to support the ASALS at both azimuthal sides. The strip-line is made of high-melting metal; thus, the ASALS SWS has a higher power capacity than microstrip SWSs. The high-frequency characteristics of that proposed SWS are investigated by using simulation software. The ASALS SWS is then fabricated and assembled for cold test. The measured transmission loss and reflection loss are better than − 2.5 dB and − 10 dB, respectively. The hot performance of the proposed is studied based on particle-in-cell (PIC) simulation. It is shown that when the operating voltage is 5700 V, the ASALS TWT can give a maximum output power of 320 W at the frequency of 39 GHz, corresponding to a gain of 14.9 dB and electron efficiency of 9.12%.