Miniaturized Dual-Band Filter Using Dual-Mode Dielectric Waveguide Resonator

This letter presents a novel miniaturized dual-band bandpass filter (BPF) using a dual-mode dielectric waveguide resonator (DWR). The DWR is a cylinder dielectric block with the surface being silver-coated. The two modes are TM010 and TM011 modes, which are used to construct the two passbands. The frequency of them can be adjusted by changing the radius and the height of the cylinder DWR and the frequency space can be controlled independently. The BPF is composed of three cylindrical cavities, which are arranged in an equilateral triangle. The three cavities construct a cascaded trisection (CT) unit, which creates a transmission zero (TZ) at the upper side of the two passbands. Finally, a dual-band BPF using DWR is simulated, manufactured, and measured to exhibit the feasibility of the proposed design. Their results are in good agreement, showing good performance, such as miniaturization, good return loss (RL), and upper stopband selectivity.