Unbalanced-/Balanced-to-Unbalanced Diplexer Based on Dual-Mode Dielectric Resonator

Abstract

The design of compact unbalanced-/balanced-to-unbalanced diplexer (U2U/B2U) based on full dual-mode dielectric resonator (DR) is investigated for the first time. The relationships of the external quality factors (Q e ) under the two modes are analyzed. It is found that the Q e of two modes can be controlled independently, which makes the design procedure simple and efficient. Based on the analysis, both of the proposed U2U and B2U diplexer can be easily built by properly adding feeding probes for the DR without increasing the circuit size by altering the location of the feeding probes according to the distribution of the electromagnetic fields. To verify the proposed design concept, the diplexers mentioned above are simulated, implemented and measured. The isolation is achieved by the orthogonality between modes while the low insertion loss is obtained due to the high unloaded quality factor (Q u ) of the dual-mode DR. The measurements are in accordance with the simulated results, showing low loss and good selectivity.INDEX TERMS Miniaturization, dual-mode dielectric resonator (DR), diplexer, design approach, unbalanced-to-unbalanced (U2U), balanced-to-unbalanced (B2U).

Very Compact Diplexer Based on Dual-Mode Dielectric TM-Mode Resonators

“…Table I summarizes a comparison between the proposed diplexer and similar designs, featuring a very compact structure, higher quality factor, spurious-free band better than 1.9 GHz (lower spurious 2.82 GHz, upper spurious 7.07 GHz), and high power levels up to 5200 W. Furthermore, the planar coupling configuration of the presented diplexer brings highly desirable advantages of easy assembly, integration, and tuning where the operation frequencies and inter-resonator couplings of the diplexer channels can be tuned independently. The isolation of the diplexer prototype is higher than 31 dB which is better than [5] and comparably similar to [6] and [8]. Alternatively, single-mode resonators can be added at the outputs to enhance the isolation similar to [2].…”

“…For example, [1] presented an L-band combline diplexer for space applications with input power up to 1800 watts. Also, a couple of dielectric diplexers were introduced to offer more size compactness and lower losses than coaxial ones based on triple-mode resonators [5], customized corner-cut [6], oval [7] dual-mode HE resonators, and TM 010 mode resonators [8], [9]. Among all, TM 010 dielectric resonators have highly desirable advantages of substantial volume-saving, mechanical stability, enhanced high-power performance, and wider spurious-free bands.…”

A wideband balanced filtering coupled‐line coupler with improved directivity based on coupled microstrip–slotline

“…When port 1 is excited, the proposed BFCLC achieves a matching bandwidth, including 10 To connect to balanced ports, the slotline-tomicrostrip transition adopted between the coupled microstrip-slotline and the port introduces a linear phase variation in Figure 3C, as its phase response does not match exactly that of the balanced port. The linear phase variation is eliminated in Work II by eliminating the slotline-to-microstrip transition.…”

“…Owing to the requirement of immunity to environmental noise, balanced circuits have attracted quite a lot of attention. [6][7][8][9][10][11][12][13] Coupled microstrip-slotline was extensively utilized in broadband microwave devices due to its quasiindependent paths for odd and even modes. [14][15][16][17][18] The recently designed coupler in Nasr and Safwat 15 used the coupled microstrip-slotline to improve the coupling and directivity of PCLCs.…”

Bandpass Filter and Diplexer Based on Dual-Mode Dielectric Filled Waveguide Resonators

“…This idea was recently applied to designing the coaxial diplexers with the characteristics of low loss and high isolation [22]. Other dual-mode resonator with high quality factors, such as the MWC [23] and the DR [24], were also utilized to design the low-loss diplexers. Similar to the BPFs, the microstrip diplexers own high losses, while the diplexers by using the coaxial resonators, the MWCs or the DRs were heavy.…”