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101.
102.
Sea-ice clutter was measured using a millimeter wave radar with frequency of 34.860GHz, beamwidth of 0.25° and pulse length of 30ns. To determine the sea-ice clutter amplitude statistics, we investigated the log-normal, Weibull, log-Weibull and K-distributions using the Akaike Information Criterion (AIC), which is more rigorous fit of the distribution to the data than the least-squares method. It is shown that the amplitude of sea-ice clutter obeys the log-Weibull distribution with shape parameters of 2.36 to 2.93 for both entire data and data within the beam width of an antenna. We propose a new log-Weibull/CFAR system uses a modified cell-averaging LOG/CFAR system. It is found that this log-Weibull/CFAR procedure is effective for suppression of sea-ice clutter and detection of target. 相似文献
103.
Xiu Yin Zhang Sheng Li Xie Bin Jie Hu 《International Journal of Infrared and Millimeter Waves》2007,28(3):223-227
A suspended planar antenna with a novel feeding structure is proposed for bandwidth enhancement. This feeding structure can
provide extra degrees of freedom to tune the antenna for compensating for the large inductance induced by the long feeding
probe. An impedance bandwidth of 56% for VSWR<2 is obtained. Simulated and measured results are compared and good agreements
are observed. 相似文献
104.
Chunheng Liu Yueguang Lu Chunlei Du Xiangang Luo 《International Journal of Infrared and Millimeter Waves》2007,28(12):1115-1122
A aperture-coupled patch antenna is designed with parasitic elements connecting to the rectangle ring on the bottom of antenna
substrate through metal vias, which lead the current induced by patch radiator to the top surface of antenna substrate. Therefore,
the effective radiation is enhanced and higher gain is achieved. The bandwidth is broadened simultaneously due to the structure
of aperture-coupled patch antenna with parasitic elements. Compared to the conventional aperture-coupled patch antenna, the
antenna gain increases averagely 2 dB due to the novel structure. Compared to patch antenna of electromagnetic band-gap, the
dimensions of novel patch antenna greatly decreases, which can be used as element in the array antenna. Two kinds manufactured
antenna are both measured in an anechoic chamber. The good agreements between numerical simulation and experimental prototype
have been obtained. 相似文献
105.
106.
Arno Jüschke Johannes Jahn Andreas Kirsch 《Computational Optimization and Applications》1997,7(3):261-276
In this paper we consider a special optimization problem withtwo objectives which arises in antenna theory. It is shown that thisabstract bicriterial optimization problem has at least one solution.Discretized versions of this problem are also discussed, and therelationships between these finite dimensional problems and the infinitedimensional problem are investigated. Moreover, we presentnumerical results for special parameters using a multiobjectiveoptimization method. 相似文献
107.
激光相位成像雷达的研究 总被引:1,自引:0,他引:1
利用无合作目标漫反射激光相位测距的原理,对关键单元技术进行分析和设计,研制成一种用于自主式车辆视觉导引的激光相位成像雷达的原理样机. 相似文献
108.
Dai Lu David Rutledge Milan Kovacevic Jon Hacker 《International Journal of Infrared and Millimeter Waves》2002,23(5):693-704
This paper presents an active patch array designed at 24 GHz. It can be used as a front-end component for a phased array. A series resonant array structure is chosen which is compact and easy excite. With 5 elements, the array proved a 12-dB antenna gain. A power amplifier and a low noise amplifier are designed on a single GaAs chip (PALNA). Bias switch is used in the PALNA, which greatly reduces the switch loss in a transceiver and increases the efficiency. 20-dB small signal gain is achieved in both power amplifier and low noise amplifier. The active patch array is built by the combination of the patch array and PALNA. The measured active gain of this antenna is 35-dB for the PA mode and 31-dB for the LNA mode. This active patch array can obtain an EIRP of 34 dBm with a total radiated power of 22dBm and a maximum PAE of 32%. To check the noise performance, we applied sources at both normal temperature and 77K (liquid nitrogen) and extracted the noise figure (3.5 dB) of the active antenna by the Y factor method. The results proved that the active antenna is working efficiently as both a transmitting and receiving antenna. 相似文献
109.
We report on various integration schemes of infrared microbolometers with microstrip antennas. The first integration design consists of two gold (Au) rectangular microstrip patches coupled along the radiating edges by a narrow niobium (Nb) strip. Devices using silicon oxide are compared to devices using amorphous silicon as antenna substrate. An extension of the twin-patch detector design is the microstrip dipole antenna-coupled microbolometer. Two ways of connecting the device to the contact pads via narrow dc leads are presented and compared. The contribution of the dc leads to the detector response is eliminated by directly connecting the dipole to the contact pads. The thermal isolation of the microbolometer from the silicon wafer is improved by incorporating air into the antenna dielectric substrate. This leads to higher detector responsivity and shifts the resonance towards longer antennas. The implementation of a bridge microstrip dipole antenna structure is also discussed. 相似文献
110.
N.P. Somasiri W.K. Toh X. Chen I.D. Robertson A.A. Rezazadeh 《International Journal of Infrared and Millimeter Waves》2002,23(12):1777-1785
This paper describes numerical modelling of a dual band multi-layered microstrip patch antenna operating at 35GHz on an in-house semi-insulating GaAs substrate. The simulated and measured resonant frequencies at both lower and upper resonant frequencies will be compared to check the accuracy of the different numerical modelling techniques. 相似文献