Experimental study of multichromatic terahertz wave propagation through planar micro-channels

Abstract

Previous theoretical and numerical studies [Y. M. Shin, Appl. Phys. Lett. 92, 092501, and 93, 221504 (2008)] have reported that a planar micro-channel with an asymmetric corrugation array supports strongly confined propagation of broadband THz plasmonic waves. The highly broad spectral response is experimentally demonstrated in the near-THz regime of 0.19 ~ 0.265 THz. Signal reflection and transmission tests on the three designed micro-channels including directional couplers resulted in a full-width-halfmaximum (FWHM) bandwidth of ~ 50-60 GHz with an insertion loss of ~-5 dB, which is in good agreement with simulation data. These micro-structures can be utilized for free electron beam and electronic/optic integrated devices.

$W$ -Band Multiple Beam Staggered Double-Vane Traveling Wave Tube With Broad Band and High Output Power

“…A good coupler is needed to be designed to decrease the refection of the TWT, Lai et al [15] and Shin et al [25] have designed several good couplers for a sheet beam TWT. But, for the sheet beam TWT, the RF signal is not naturally cut off in the sheet beam tunnel; they have to design an input/output connector in their coupler to prevent RF signal from entering the electron gun, which lead the coupler to be somewhat too long for the beam transport and too complex to be fabricated.…”

“…In this paper, Transmission characteristics of a 52-period SWS together with two transition structures. refer to [25], a three-period transition structure is designed as shown in Fig. 8, and with the other parameters unchanged, the groove depth dy = k n -k n−1 and the width of the input port Z are changed step by step to adjust the transmission characteristics appropriately.…”

Photonic Crystal-Coupler for Sheet Beam THz Vacuum Electron Tubes

“…The wide cross section of the beam tunnel required in sheet beam VEDs, behaves as a waveguide over cutoff, leading to a relevant portion of the signal propagating in the beam tunnel rather than in the coupler port, with consequent degradation of performance ( Fig.1). So far, appropriate impedance mismatches have been added in the beam tunnel to obtain the required isolation of the beam aperture [15]. However, this approach results in an increased complexity of geometries and fabrication.…”

Experimental demonstration of a terahertz extended interaction oscillator driven by a pseudospark-sourced sheet electron beam

“…[8][9][10][11][12][13][14][15] A sheet electron beam is very attractive due to its enlarged beam cross section area and reduced space charge effect, however the focusing and formation of a sheet electron beam is challenging especially when the beam has to be propagated down through a THz structure of small transverse cross-section. [16][17][18][19][20][21] A very high current electron beam capable of being transported through a THz interaction circuit can be realized by combining the advantages of the PS-EB and the sheet electron beam geometry. Detailed analysis and design regarding this EIO has been presented in our early work 12 , and this letter will focus on the experimental demonstration.…”