摘要：In this paper, the concept of the Shortest-Route Traffic Matrix(SRTM) was first presented, and the generalized formula for computing ring capacity requirement in use of SRTM is given. Then, a new capacity design algorithm which is based on SRTM was presented for Synchronous Digital Hierarchical(SDH) Bi-directional Self-Healing Ring (BSHR). The algorithm simulation results demonstrate that this algorithm is very efficient for SDH BSHR capacity design and can make less project investment and make high utilization of lines and equipment. By means of the algorithm in this paper, capacity optimization assignment for SDH Hierarchical Self-Healing Ring (HSHR) and for ATM Virtual Path (VP)-based Self-Healing Ring (SHR) is also discussed.

摘要：Considering the shortcomings of the existing vehicle-to-vehicle（V2V） communication antennas, this paper proposes a regular hexagon broadband microstrip antenna. By loading shorting pins and etching V-shape slots with different size at each angle of the regular hexagon patch, it realizes impedance matching and obtains better impedance bandwidth. The simulated results show that the relative bandwidth of this antenna reaches 35.55%, covers the frequency band of 4.74 GHz to 6.79 GHz. The antenna acquires an omni-directional radiation pattern in the horizontal plane whose out of roundness is less than 0.5 d B. In addition, the antenna is manufactured and tested, whose tested results are basically consistent with simulated results. Because the height of antenna is 3 mm, it is easy to be hidden on roof of a vehicle for V2 V communication.

摘要：Given the flaws in traditional cascading design of the filtering antennas, a kind of filtering antenna based on the defected ground structure （DGS） is proposed. It adopts the method of co-design to integrate the filter and the antenna into one substrate, resulting in a miniaturized size of 34 mmx30 ram. In the design, the structure with dumbbell shape is etched on the ground of dual-band antenna, aiming for the low-pass property of the filtering antenna. The simulated results show that the filtering antenna＇s co-design can effectively enlarge the bandwidth of the pass-band and suppress the bandwidth of T-patch, whose pass-band can cover the bandwidths of wireless local area network （WLAN） 21~ GHz, wideband code division multiple access （WCDMA） 2.1 GHz, long term evolution （LTE） 2.3/2.5/2.6/2.8 GHz etc. In addition, the filtering antenna＇s physical module is fabricated and measured, whose test results are basically consistent with the ones of simulation. Moreover, the filtering antenna with liner polarization has a good radiation pattern of omni-direcfion, and can be applied to the terminals of wireless mobile system.

摘要：This paper presents a modified circular-cut multiband fractal antenna with good radiation patterns designed for digital cellular system（DCS）, personal communication system（PCS）, 2.4/5.2/5.8 GHz wireless local area networks（WLAN） and 2.5/3.5/5.5 GHz worldwide interoperability for microwave access（WiMAX） applications simultaneously. Originally, the modified circular monopole antenna is designed to resonate at around 2.1 GHz and 3.6 GHz. After subtracting the circular iterative tree fractal structure, it can produce three other resonances at around 5.6 GHz, 6.47 GHz and 7.89 GHz. Besides, as the number of iterations increases, not only do the new frequency bands appear（it demonstrates the good self-similarity property of the proposed antenna）, but also the operating bands shift from high frequency to low frequency（it shows the well space filling property）. Furthermore, the proposed antenna owns a compact structure, which can achieve the 5.28 dBi of relative high gain. And the measured results are basically accordant to simulated results, which proves the effectiveness of the proposed antenna.

摘要：Constellations design for regional terrestrial-satellite network can strengthen the coverage for incomplete terrestrial cellular network. In this paper, a regional satellite constellation design scheme with multiple feature points and multiple optimization indicators is proposed by comprehensively considering multi-objective optimization and genetic algorithm, and "the Belt and Road" model is presented in the way of dividing over 70 nations into three regular target areas. Following this, we formulate the optimization model and devise a multi-objective genetic algorithm suited for the regional area with the coverage rate under simulating, computing and determining. Meanwhile, the total number of satellites in the constellation is reduced by calculating the ratio of actual coverage of a single-orbit constellation and the area of targets. Moreover, the constellations' performances of the proposed scheme are investigated with the connection of C++ and Satellite Tool Kit(STK). Simulation results show that the designed satellite constellations can achieve a good coverage of the target areas.

摘要：A novel, compact, and highly selective ultra-wideband （UWB） bandpass filter with a narrow notched band is presented. Apart from having a basic structure of a slotline multiple-mode resonator （MMR） and microstrip feed lines, this novel design introduces a cross-coupling between the input and output feed lines to enhance the filter selectivity. The design strictly follows the theory and verified by electromagnetic （EM） simulation and experiments. In addition, the narrow notched band is introduced by embedding a pair of split ring resonators （SRR） in order to reject any undesired existing radio signals that may interfere with the Federal Communications Commission （FCC）-defined UWB band. By changing the structural parameters of SRR, it can be easily tuned to any desired frequency. This filter can be integrated in UWB communication systems and efficiently improve the interference immunity from undesired signals such as wireless local area network （WLAN）.

摘要：A broadband reflective polarization converter is proposed. The unit cell of polarization converter is composed of a single-split resonant ring, a double-split resonant ring, a dielectric substrate and a metallic ground. The simulated results show that the polarization converter can convert x-polarized waves into y-polarized waves and obtain a broadband polarization conversion from 0.501 0 THz to 1.390 0 THz with the polarization conversion ratio(PCR) beyond 80% at normal incidence. Moreover, the surface current distributions are investigated to explain the polarization conversion mechanism. Finally, a good agreement is achieved between simulated and measured results. The polarization converter can be applied in terahertz imaging, communication and stealthy technology.

摘要：A reflective beam splitter is proposed and verified. The unit cell of the beam splitter is composed of a metal pattern, a dielectric substrate, and a metallic ground. Each subarray structure of the device is composed of four unit cells, which are gradually rotated at 45°. The horizontal and vertical subarrays form a 4×4 gradient metasurface supercell. In the operating frequency band, the incident linearly polarized terahertz wave is reflected and divided into four beams of approximately equal power but different propagation directions. The proposed terahertz beam splitter based on metasurface has the advantages of small size, low cost and easy processing, and can be applied to terahertz stealth and imaging.

摘要：In this paper,we report the design and simulation of a bias-selectable dual-band photodetector operating in the visible(VIS)and near infrared(NIR)*** photodetector consists of two back-to-back avalanche photodiodes(APDs)with InGaAs and Si absorption layers *** structure and electrical and optical properties of the dual-color photodetector were designed and simulated by exploiting Silvaco *** results obtained on the basis of numerical simulation include the current-voltage,capacitance-voltage,spectral response,*** optical simulation shows the detection capability in the VIS and NIR ranges,cut-off wavelengths of 1.0μm and 1.8μm depending on the applied bias *** with using the PIN structure as element device,the dual-band photodetector based on the APD configuration could detect the very weak signal,realizing few photons,even single photon detection.

摘要：A novel fluid sensing system based on side-polished optical fiber(SPOF)is proposed,which realizes the fluid replaceability and effective refractive index(RI)sensing *** investigations demonstrate that the photonic bandgap effect can be obtained if the RI of liquid is higher than that of substrate material in the wavelength range *** relationship between bandgap edge wavelength and RI is studied *** SPOF with a depth of 57μm is used in the experiment to realize the construction of the fluid *** filling three different liquids,the result shows that the wavelength of the bandgap edge has a red shift with RI increased,which is nearly linear in the RI range of 1.56—1.6 with a sensitivity about 5543.64 nm/*** proposed sensing system can be flexibly applied to the field of fluid characteristic sensing such as biochemical solution characteristic detections.