Papers by Keyword: Broadband

Abstract: A broadband multi-layer radar absorbing coating (RAC) and transparent shielding film (TSF) operating within the frequency range of 7 to 12 GHz are designed and fabricated for the purpose of a radar cross section (RCS) reduction of complex naval targets such as submarines and ships. The proposed RAC consists of three layers, a shop primer, a main absorbing material, and epoxy resin paint. In addition, a TSF was fabricated by coating an ITO/Ag/ITO multilayer on a polyethylene terephthalate (PET) substrate using roll-to-roll DC plasma deposition technique. The experimental results demonstrate that the proposed RAC guarantees an RCS reduction of 10 to 15 dB from 7 to 12 GHz.

Abstract: A single resonance frequency is the main factor of limiting vibration energy collector efficiency. In this paper, the multi degree of freedom oscillation adjusting bandwidth scheme is reported, designing a kind of new broadband vibration energy harvester, which has multi-mode energy acquisition, multi freedom vibration and broadband characteristics. Firstly, Broadband energy collector structure design. Secondly, Combining with the main vibration form, using the ANSYS carried out a detailed analysis of its working model. Finally, designing the prototype and doing some experimental verification, the results show that the designed energy collector with low frequency and wideband energy acquisition performance, the frequency domain of energy collection is 57.6 to 69.45HZ ,which break through the bottleneck of traditional single resonance frequency of energy acquisition, has a high value of theory and engineering application.

Abstract: according to the special requirements of quantum optics experiments, through the optimum design of broadband low noise amplifier circuit, this paper developed a broadband low noise photoelectric detector. We focus on the analysis of the factors affecting the photoelectric detector gain, bandwidth and noise, by a suitable choice of the photodiode, a sampling resistor, feedback resistor and capacitor, the broadband low noise photoelectric detector. Experiments show that, this circuit can be used for broadband low noise quantum communication circuit.

Abstract: In this paper, a hybrid quasi-micro-pyramid structure is fabricated via nanosecond pulse laser micro-processing, which demonstrates a 15% drop in average reflectance as compared to the uniform quasi-micro-pyramid structures. The influences of laser fluence, pulse number, and designed pitch are also studied experimentally and systematically. The results show that reflection increases with the pattern pitch, decreases with pulse number, and a minimum in reflection is reached at a laser fluence of 4.83 J/cm2. The method here demonstrated provides an alternative and low-cost solution for broadband anti-reflection by hybrid structures with normal aspect ratio rather than uniform structures with high aspect ratio. Higher antireflection performance can be expected by optimizing the laser processing parameters.

Abstract: The curtain array was usually composed of folded dipoles as elements for their high input impedance, but its bandwidth had a limitation for its antenna mode. This paper proposed a method for broadband folded dipoles using branch arms for current redistribution, which increased the bandwidth of input impedance and VSWR effectively by choosing the proper positions of the branch wires. The current distribution on branch model showed an unbalanced condition as the branch wires moved. As verification, a practical model with cage antenna had been analyzed by the present method and FEKO. The results illustrated that when factor k was between 0.4 and 0.5, the bandwidth would be maximum.

Abstract: A high isolation and compact microstrip diplexer for broadband and wireless local area network (WLAN) application is proposed in this paper. It is achieved by using the combination of a broadband bandpass filter (BPF) composed of one open stub and two short stubs of different size loaded in 50Ω feed lines. The tapped stub can not only generate two zeros to deepen the stopband, but also connect other BPF without deterioration of in-band performance. Hence, the compact diplexer combines two BPFs without extra junction matching network. The mutual loading effect approximately equivalent to a coupled resonator can create one zero at the passband edge to improve the isolation. The proposed microstrip diplexer is designed and fabricated, and it has a 1dB fractional bandwidths (FBW) of 60% at 3.5GHz for broadband channel and 3% at 5.8GHz for WLAN channel . The simulated and measured results are presented and good agreement is obtained.

Abstract: In this paper, a novel broadband circularly polarized (CP) slot antenna is proposed and fabricated, in which the perturbation configuration with two quarter annular rings fabricated cornerways in the square slot is designed and a simple Photonic-bandgap (PBG) structure is employed. Through simulating and testing, the broad impedance bandwidth of 81.5%(VSWR<2.0) and the 3dB axial ratio (AR) bandwidth of 48.2% are achieved respectively. This slot antenna will be widely utilized in communication field. These instructions give you basic guidelines for preparing papers for conference proceedings.

Abstract: The problem of frequency band of acoustic transducer is the key research field. By summarizing of Tonpilz and Janus-type transducer influence factors,such as transducer structure type, geometry parameters, the rule of redressing the mechanical quality factor Q_m is investigated, and the trend of extending the frequency band by multi-mode coupling is got. By analyzing the multi-modal forms of vibration of double and triple resonance resonant, several types of extending frequency band of transducer are categorized under this forms. The advantages and disadvantages are investigated by general theory analysis of extending longitudinal vibration transducer, and the state of the art and the applications are displayed. So that the researchers are easier to understand the transducer, and can offer ideas for new design.

Abstract: An Ultra broadband power amplifier module based on GaN HEMT is studied. TGF2023-02 Chip of GaN HEMT from TriQuint Corporation is adopted and modeled first. The amplifier is designed with negative feedback technique. DC bias circuits and microstrip matching circuits are simulated and optimized carefully. Simulation results show that the amplifier module has a wide range frequency response from 3 to 8 GHz. It exhibits power gain of 7.6 dB, an output power of 37.5dBm under DC bias of V_ds = 28 V, V_gs = -3.6 V at the frequency of 5.5 GHz.

Abstract: DEP (dielectrophoresis) technology has been widely researched and applied in measurement the properties of various of biological particles. The design for every part to the whole system has been completed based on the requirement of broadband and wide-amplitude drive power in dielectrophoresis. As well as, the source and output detected feedback system are been designed respectively to ensure the output signals amplitude and phase of 4 channel is synchronous. Amplitude detect uses the double diode with temperature compensation to make up the detect circuit, the theory analysis and simulation of it has been performed. Experimental results show that the accuracy reach 5%, resolution 1v.