Lee Eui Su, Lee Sun-Goo, Kee Chul-Sik, Jeon Tae-In
Division of Electrical and Electronics Engineering, Korea Maritime University, Busan 606-791, Korea.
Opt Express. 2011 Aug 1;19(16):14852-9. doi: 10.1364/OE.19.014852.
We present a tunable notch filter having a wide terahertz (THz) frequency range and a low-pass filter (LPF) having a 0.78 THz cutoff frequency. Single slit and multiple slits are positioned at the center of air gaps in tapered parallel-plate waveguides (TPPWG) to obtain the notch filter and LPF, respectively. The notch filter has a dispersion-free and low-loss transverse magnetic (TM) mode. The Q factor was proved to be 138, and the resonant frequency is easily tunable by adjusting the air gaps between TPPWG. On the other hand, the cut off frequency of the LPF was determined using a Bragg stop band, which depends on slit period. The LPF has a transition width of 68 GHz at the cutoff frequency and a dynamic range of 35 dB at stop bands. In addition, the characteristics of such filters were analyzed using finite-difference time-domain (FDTD) simulations.
我们展示了一种具有宽太赫兹（THz）频率范围的可调谐陷波滤波器以及一种截止频率为0.78 THz的低通滤波器（LPF）。单缝和多缝分别位于渐变平行板波导（TPPWG）气隙的中心，以分别获得陷波滤波器和低通滤波器。该陷波滤波器具有无色散且低损耗的横向磁（TM）模式。经证明，品质因数为138，并且通过调整TPPWG之间的气隙，谐振频率易于调谐。另一方面，低通滤波器的截止频率是使用布拉格阻带确定的，该阻带取决于狭缝周期。该低通滤波器在截止频率处的过渡宽度为68 GHz，在阻带处的动态范围为35 dB。此外，使用时域有限差分（FDTD）模拟分析了此类滤波器的特性。
