Shi-Fen Feng

Triple-Mode Dielectric Resonator Diplexer for Base-Station Applications

This paper proposes a novel diplexer based on triple-mode dielectric-loaded cylindrical cavities. Such two metal cavities are designed to achieve two different frequency bands, while three resonant modes of a single cavity are classified as a TM mode and a pair of hybrid (HE) degeneration modes. An off-centered dielectric resonator instead of a traditional corner cuts perturbation or screws perturbation properly perturbs the two degenerate modes in the same cavity. Extensive study is then conducted to design this proposed diplexer. Finally, a diplexer prototype is fabricated using a brass cavity and it is tested for experimental verification of the predicted results. Good agreement between measurement and simulation is achieved.

Triple- and Quadruple-Mode Wideband Bandpass Filter Using Simple Perturbation in Single Metal Cavity

This paper proposes a novel class of wideband metal cavity multiple-mode bandpass filters (BPFs), consisting of a triple-mode filter and a quadruple-mode filter. Two TE11 degeneration modes in a single metal cavity are excited by using an off-centered approach instead of a traditional corner-cut approach. They work together with the TM10 mode to constitute a three-pole wide passband with a fractional bandwidth of 30% at the central frequency of 3.2 GHz. Moreover, an off-centered metal cylinder can properly excite an extra TM11 mode in the passband. As such, this TM11 mode, TM10 mode, and a pair of degeneration TE11 modes can be simultaneously utilized to form a quadruple-mode BPF. Compared with the triple-mode BPF, the quadruple-mode BPF has better performance in term of the steepness of rejection skirt. The fractional bandwidth of this BPF can achieve up to 31%. In final, the two proposed BPFs are fabricated by using the silver plated aluminum technology. Measured S-parameter frequency response and group delay have satisfactorily matched with the simulated results.

Triple-Mode Dielectric-Loaded Cylindrical Cavity Diplexer Using Novel Packaging Technique for LTE Base-Station Applications

This paper proposes a triple-mode dielectric-loaded cylindrical cavity diplexer by using a novel packaging technique for long term evolution (LTE) base station applications. Four metal cavities, loaded by a triple-mode dielectric resonator (DR), are designed to resonate at two different frequencies for the diplexer operation. In this context, three resonant modes of a single cavity are classified as a TM mode and a pair of hybrid degenerate modes (HE modes). The two degenerate modes in the same cavity are properly excited by employing an off-centered DR instead of a traditional corner-cut structure as a perturbation element. Finally, such a diplexer is designed and fabricated, and good agreement between measurement and simulation is achieved.

A Triple-mode Wideband Bandpass Filter Using Single Rectangular Waveguide Cavity

A triple-mode wideband bandpass filter (BPF) is proposed in this paper. Three resonant modes, namely, TM01 mode and A pair of TE11 degenerated modes, have been excited in single rectangular waveguide cavity. Meanwhile, a wide pass bandwidth have been realized and the fractional frequency bandwidth of about 29% is achieved at the central frequency of 3.1 GHz. Finally, a filter sample is fabricated and tested. The measured results are well matched with the simulated one.

A Quintuple-mode Wideband Bandpass Filter on Single Metallic Cavity With Perturbation Cylinders

A quintuple-mode wideband bandpass filter (BPF) on a single circular waveguide cavity with perturbation-oriented cylinders is proposed. These five resonant modes are the fundamental TM01 mode, a pair of TM11 degenerate modes, and a pair of TE11 degenerate modes. Three metallic cylinders are installed on the bottom of an intra-cavity to excite TM modes, and two coaxial feed probes are used to further separate the paired TE11 modes. A wide passband under the resonance of these five modes is achieved with 36% fractional bandwidth. To prove the validity, the proposed filter is fabricated using silver-plated aluminum metal cavity. The measured results are in good agreement with the simulated results.

Multi-mode wideband bandpass filters using waveguide cavities (invited)

A novel class of miniaturized multi-mode wideband bandpass filters (BPFs) is introduced this paper, includes four multiple-mode filters. Two of them are realized using metal cavity and two of them are realized using substrate integrated waveguide (SIW). These filters have significant advantages in size reduction which can reduce 2.5-4 times compared with traditional single-mode cavity filter. The fractional bandwidth of three filters achieves 30%, 31% and 42%, respectively. All three BPFs are analyzed and experimentally demonstrated. Comparisons of the measured and simulated results are presented and in good agreements with each other.

Multi-Mode Bandpass Cavity Filters and Duplexer With Slot Mixed-Coupling Structure

The quasi-elliptic multi-mode bandpass cavity filters and duplexer with slot mixed-coupling structure are proposed in this paper. A single metal cavity embedded with a rectangular- shaped slot-cut metal plate is utilized to constitute a multi-mode bandpass filter with a few features including wide passband, low profile and controllable transmission zeros (TZs). In this paper, the slot-cut metal plane serves as the multi-mode resonators. In detail, the slot on the metal plane functions as the circuit element to move the higher order modes within the reasonable frequency-band, while serving as a mixed-coupling structure to generate out-of-band transmission zeros. To demonstrate the multiple-mode capability in filter design, the dual-mode, triple-mode, and quadruple-mode filters are developed by appropriately allocating a few TZs in the upper stopbands using the proposed slot mixed-coupling approach, namely, Type-I filters. Next, a quadruple-mode cavity filter with both lower and higher TZs is designed, namely, Type-II filter, which is further applied for the exploration of a duplexer. Finally, the filter and duplexer prototypes are fabricated and measured. The measurement results are found in good agreement with the simulated ones.

Triple-mode wideband bandpass filter using single rectangular waveguide cavity

A triple-mode wideband bandpass filter (BPF) is proposed. It consists of a single rectangular waveguide cavity with two small metal rods to be inserted into the cavity from input/output feeding ports. As such, one TM110 mode, one TM210 mode, and one TM130 mode can be simultaneously excited in this cavity to form up a wide frequency passband. The fractional bandwidth is 58% at center frequency of 5.5 GHz with low insertion loss (<0.5 dB). Furthermore, this design approach is good for miniaturization compared with traditional single-mode filter. For validation, a proposed filter is fabricated using silver-plated aluminum metal cavity. Both theoretical and measured results are presented with good agreement.

Cross-coupling on microstrip line for substrate integrated waveguide (SIW) quasi-elliptic bandpass filter

This paper proposed a quasi-elliptic bandpass filter on substrate integrated waveguide (SIW) cavity with cross-coupling structure using microstrip line. Etched slots on the SIW cavity are used to produce electric coupling between two adjacent SIW resonators, the cross-coupling is obtained by a microstrip-line with embedded stubs above the SIW cavity. By using cross-coupling and embedded stubs, a SIW filter is constituted with transmission zeros at both sides of the passband. Finally, a third-order SIW quasi-elliptic filter at 3.7GHz is designed and fabricated in a two-layer substrate. The measured results are found in good agreement with the simulated ones.

An improved compact substrate integrated waveguide (SIW) bandpass filter with sharp rejection and wide upper-stopband

An improved compact substrate integrated waveguide (SIW) bandpass filter based on quarter-mode substrate integrated waveguide (QMSIW) is proposed in this paper. QMSIW bandpass filter has good performance and many advantages such as compact size, low insertion loss and easy integration, but narrow upper-stopband and bad rejection skirt still need to be improved. Source-loaded coupling structure can produce a pair of transmission zeros to sharpen the rejection skirt, and the upper-stopband can be further improved by utilizing lowpass filter. By using above methods, an improved filter has been designed and simulated, the simulated result shows that the filter has sharp rejection skirt and wide upper-stopband.