A one-third triangular resonator with two electric walls and two virtual magnetic walls is proposed for the design of a broadband filter. The structure is realised by taking out one-third of an equilateral or isosceles triangular resonator of the substrate integrated waveguide and therefore it is called the one-third-mode substrate integrated resonator (OTMSIR). The characteristics of the OTMSIR cavity are studied. Based on this resonator, a filter composed of six OTMSIR cavities is designed, fabricated and tested. The measured results agree well with the simulated ones.Introduction: Owing to numerous advantages such as minimal size, high quality factor, low insertion loss, high power capability, low cost and easy integration in a standard PCB or low-temperature co-fired ceramic, substrate integrated waveguides (SIWs) and substrate integrated circuits (SICs) have been widely applied to the designs of microwave and millimetre-wave circuits and systems since they were proposed in recent years. A large number of papers have studied the rectangular and circular SICs, but there is very little investigation concerning triangular SICs. Thanks to this particular structure, the components of a triangular SIC are very compact [1]. Therefore, it is worth placing more attention on the research of the triangular SICs.The half-mode SIW (HMSIW) and quarter-mode SIW (QMSIW) have also been proposed recently in order to reduce the size of the original SIW and they are better able to meet the requirements for miniaturisation in modern wireless telecommunications. Having the same excellent performance of its predecessor, the HMSIW technique has been applied to many microwave components [2][3][4]. The Q-factors of microwave components based on HMSIW and/or QMSIW resonators are usually low, due to the related virtual magnetic walls that may cause some radiation losses. However, their internal coupling coefficients are much stronger than those of conventional SIWs. For these reasons, they are typically used to design bandpass filters with moderate or high bandwidths which conventional SIW filters cannot easily achieve. The fractional bandwidths of the HMSIW and QMSIW filters in [3,4] are 14 and 26%, respectively.The one-third-mode substrate integrated resonator (OTMSIR) can be extracted from an equilateral or isosceles triangular resonator of a SIW. Fig. 1 illustrates the structure of the OTMSIR, which is generated by bisecting the triangular SIW cavity along the perpendicular bisectors. Compared with the original metallic triangular substrate integrated resonator (MTSIR), the new OTMSIR has a more compact structure. However, its resonant frequency will be a little lower than that of the MTSIR due to the leakage. The Q-factor of the OTMSIR is also lower due to the virtual magnetic walls. Like the HMSIW and the QMSIW, the OTMSIR may be a candidate for designing broadband bandpass filters. In this Letter, all the OTMSIRs are extracted from equilateral MTSIRs and they are all built from the substrate Rogers 5880 with a thickness of 0.8 mm...
Communication resource allocation and collision detection are important for the Ad Hoc network. Considering the existing TDMA-MAC protocol, the allocation way based on fixed time slot is mostly adapted, which cannot guarantee the performance and be not flexible about the business for different nodes in the distributed network. Desynchronization, as a biological term, can be utilized in the Ad Hoc network. It implies that sensor nodes interleave periodic events to occur in succession through negotiation and adjustment. In this paper, we design a MAC protocol(MD-MAC) in the multi-hop network based on the idea of Desynchronization to solve the problem caused by stale information and lay down the adjustment rule to allocate the communication resource. Also, we propose a scheme which the network can detect collision in a self-adapting way. Finally, we simulate the proposed protocol to evaluate the performance. The experimental results indicate that the proposed algorithm can accelerate the convergence speed of resource allocation, solve collision and improve the efficiency of the distributed network.
A one‐third triangular resonator with two electric walls and two virtual magnetic walls is used to realize a compact wideband bandpass filter. This structure is fulfilled by taking out an isosceles or equilateral triangular resonator of substrate integrated waveguide (SIW) version and therefore, it is called one‐third‐mode substrate integrated resonator (OTMSIR). Based on one single cavity, a quadruple‐mode technique is used to design a compact filter by adding an elliptical metallic via‐hole and using detected ground structure (DGS). Finally, a 12.6 GHz bandwidth planar quadruple‐mode filter is fabricated and tested. The measured results agree well with the simulated ones. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1993–1996, 2016
In this paper, we propose a novel distributed TDMA protocol based on the Multi-Arms Bandit model for the dynamic UAVs environment. Because of the frequent topology changes of UAVs, we consider a distributed communication protocol, which do not require the maintenance of accurate network topology information. Through the adaptive interaction between nodes, perceiving the surrounding topology environment and learning from historical experience, each node in the network can transmit information in a fast collision-free way. Also, the MAB model is utilized in our protocol, so that the time slot can obtain sufficient multiplexing rate through multiple rounds of node selection. Experiments show that the protocol can achieve better throughput and fast enough convergence speed, even in the case of high network density, and scales well with the size of the network.
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