Equivalent-circuit representation and explanation of attenuation poles of a dual-mode dielectric-resonator bandpass filter

Abstract

of the effects of a resistively coated upper dielectric layer on the propagation characteristics of hybrid modes in a waveguide shielded microstrip using method of lines," IEEE Trans. . L. Foo and P. P. Silvester, "Boundary-marching method for discontinuity analysis in waveguides of arbitrary cross section," IEEE Trans.Abstract-A =4 rectangular-waveguide resonator of square cross section filled with high-permittivity ceramics has two degenerate lowest modes. A dual-mode bandpass filter based on this structure is studied, focusing on the attenuation poles at both sides of the passband. It is described how to achieve capacitive and inductive coupling between dominant modes of a resonator of square cross section. An equivalentcircuit model is proposed, including mode coupling, excitation from the external circuit, and direct coupling between input/output (I/O) electrodes. Equivalent-circuit parameters are measured and their validity is verified using simulated result. Appearance and annihilation of the attenuation poles are successfully explained by the proposed model, and attenuation pole frequencies are controlled by shifting the I/O electrode transversely.

A Wideband and High Rejection Multimode Bandpass Filter Using Stub Perturbation

“…The other way for the filter size reduction is to modify the traditional resonator to generate additional modes, causing the resonator to have multiple resonate frequencies and thus one physical resonator can be treated as multiple electrical resonators. Examples can be seen from the dual-mode ring resonator [7], [8], dual-mode rectangular patch [9], dual-mode triangular patch [10] and dual-modes circular patch. Recently, a five-pole filter was built based on a single triple-mode stepped-impedance resonator (SIR) [11] for ultra-wide bandwidth application (UWB).…”

A broadband perpendicular E‐plane waveguide‐to‐suspended stripline transition

“…The first patch, on the other hand, plays the role of source-load cross-coupling and its dimension, W P1 , modifies the out-of-band response. A larger W P1 results in a larger cross-coupling between source and load, resulting in a frequency shift of the transmission zero toward the center frequency [7], as can be seen in Figure 3(b). The transition design is simulated using Ansys HFSS.…”

“…As to the design of dualband antenna, the most common way is to use two branches with different length to reach dual-band [5,6], or to use dual frequency exciting mode so that a path can produce two frequencies [7]. Some multiband antennas are designed by stretching a dualband antenna and adding quarter wavelength branch under a certain frequency [8,9], or digging a slot on ground so that another resonance path is produced [10].…”

A novel planar multimode bandpass filter with radial perturbation

“…In addition, multiband operation covering GSM850 (824 -894 MHz), GSM900 (890 -960 MHz), GSM1800 (1710 -1880 MHz), GSM1900 (1850 -1990 MHz), and UMTS (1920 -2170 MHz) for wireless wide area network (WWAN) operation is also a must for the promising internal antennas. The reported multiband internal mobile phone antennas such as the planar inverted-F antenna (PIFA) with multiradiating strips [1,2] or Hilbert-type radiating strips [3], the loop strip antenna [4,5], and the like, however, show a high profile of about 6 -10 mm above the system ground plane of the mobile phone. It is also possible to achieve a lowered profile of about 3-4 mm for the PIFA [6,7]; however, with which multiband operation for covering all the five operating bands for WWAN operation is difficult to obtain.…”

“…The concept was firstly adopted in the compact waveguide filter design [1]. Later on, the multimode filter design was also adopted in the planar circuits, for examples the dual-mode ring resonator [3,4], dual-mode rectangular patch [5], dual-mode triangular patch [6], and dual-modes circular patch. Recently, a five-pole filter was built based on a single triple-mode stepped-impedance resonator (SIR) [7] for ultra-wide bandwidth application (UWB).…”