Analysis and Design of a Diplexer for Satellite Communication System

Abstract

This paper presents the design and analysis of a diplexer for satellite communication system based on hybrid spoof surface plasmon polariton (SSPP) and substrate integrated waveguide (SIW) transmission lines. The proposed diplexer consists of a SSPP printed line composed of H-shaped periodical grooved strips to operate as a low pass filter and a SIW to operate as a high pass filter. The operating frequency bands of the proposed diplexer are from 11.7 to 12.75 GHz for the downlink (DL) band, and from 17.3 to 18.35 GHz for the uplink (UL) band. These frequency bands correspond to the operating frequencies in Nile Sat 201 system. The frequencies of the DL and UL bands are adjusted independently by tuning the structure parameters of SSPP and SIW sections, respectively. The proposed hybrid SSPP-SIW diplexer is fabricated and measured. Simulated and measured results show good channel isolation, low return loss and low insertion loss in the required frequency bands.

Substrate Integrated Waveguide Multiband Bandpass Filters and Multiplexers: Current Status and Future Outlook

“…6. As can be seen, various matching networks can be exploited and combined with diverse SIW single-band BPFs to develop SIW multiband BPFs and multiplexers based on this scheme, embracing multiport wideband T-junctions based on SIW [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38] or microstrip [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53] technologies, circulators [31], manifolds [32], coupling apertures [54], [55], switches [56], shared feeding ports [57],…”

“…Microstrip T-junctions are the other type of frequently used matching circuits in the development of SIW multiband BPFs and multiplexers [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53] thanks to their wideband matching characteristics and significant flexibilities. The representative works using microstrip T-junctions have been described in Fig.…”

“…8(b). For a further circuit miniaturization, SIW loading techniques including CSRRs-loaded SIW [49], composite right/left-handed (CRLH) cells-loaded SIW [50], spoof surface plasmon polariton (SSPP) [51] and SSPPs-loaded SIW [52], [53] schemes were applied to realize at least one channel of the diplexers or triplexers, as the two prototypes shown in Fig. 8(c).…”

“…18. Some of these schemes have also been applied to design miniaturized SIW multiband BPFs and multiplexers, such as using LTCCbased multilayered configurations [40], [62], [69], [73], [75], [111], [131], partial-mode techniques [53], [64], [82], [90], [94], [105]- [107], [128], folded [25] and ridged [32] schemes, and metamaterial cells-based solutions [33], [34], [35], [36], [37], [49], [50], [51], [52], [53]. It is worthwhile mentioning that these miniaturization schemes would usually lead to the increasing of transmission loss of an SIW transmission structure or the lowering Q u of an SIW resonant cavity.…”

“…Because all the multiple passbands operate below the cut-off frequency of SIW transmission structure, miniaturization can be achieved for this kind of loading solutions. Nevertheless, it is usually difficult to realize cross-coupled topologies except conventional inline topologies, and the self-packaged characteristic of SIW structures would be destroyed due to the radiation property of CSRRs, needless to say lowering their unloaded quality factors Q u s.Microstrip T-junctions are the other type of frequently used matching circuits in the development of SIW multiband BPFs and multiplexers[39],[40],[41],[42],[43],[44],[45],[46],[47],[48],[49],[50],[51],[52],[53] thanks to their wideband matching characteristics and significant flexibilities. The representative works using microstrip T-junctions have been described in Fig.8.…”