Dual‐wideband bandpass filter using multilayer broadside‐coupled structure

Abstract

The paper presents a dual‐wideband bandpass filter using multilayer broadside‐coupled microstrip‐coplanar waveguide (CPW) structure. The half‐wavelength stepped‐impedance resonators at the top and bottom layers are broadside coupled in the vertical direction through a CPW‐multimode resonator (CPW‐MMR) at the mid layer, which forms a mixed MMR. The ultra‐wideband obtained from tight coupling is split into two passbands by introducing extra transmission zeros, good impedance matching is achieved by adopting open‐ended microstrip stubs on the input and output microstrip feed lines, and the dual‐wideband characteristic is realized. The proposed filter is small in size, and its operation bands and the bandwidth of the stopband are adjustable. Both experiments and computer simulations were conducted, and the measured results are in good agreement with the simulation results.

Interference in Coupled Structures with Strongly Un-balanced Phase Velocities of Normal Waves and its Electromagnetic Analogy with "Tsunami"

“…These coefficients are generally not equal, so when propagating "e" and "o" waves in coupled lines with different phase velocities, their vector addition occurs. Therefore, the phase shifts of waves "e" and "o" due to inequality γ e and γ o depend on the oscillation frequency, and in the coupled lines there is a frequency dependence of transmission and reflection coefficients [34][35][36][37][38][39][40][41][42][43].…”

Novel 6‐GHz/80.8% fractional bandwidth filtering power divider with ultra‐large coupling coefficient using air‐dielectric broadside‐coupled lines

“…Filtering power divider (FPD) [1][2][3][4][5][6][7][8][9][10][11][12] shows obvious advantages in frequency selectivity, compared with the traditional power divider. With the development of wideband communication multi-input and multioutput (MIMO) technology, the FPD with large bandwidth is highly required in the system.…”

“…Until now, several filtering circuits with broadside-coupled lines are reported. [10][11][12] In the reported results, highperformance dielectric materials, including Rogers, 10 LTCC 11 , and metamaterial, 12 are usually adopted. The corresponding fabrication processes are very complex, which inevitably increase the cost and degrade the property.…”

“…Broadside‐coupled lines can be used to realize tight coupling with large coupling coefficient, which is always considered as simple and effective solution for the wideband bandpass filter. Until now, several filtering circuits with broadside‐coupled lines are reported 10–12 . In the reported results, high‐performance dielectric materials, including Rogers, 10 LTCC 11 , and metamaterial, 12 are usually adopted.…”