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In this paper, the photoconductivity of silicon is characterized in measurement in two mm-wave bands: 110GHz – 170GHz and 220GHz – 325GHz. It is shown that in the mm-wave bands the silicon has a low loss under dark condition but becomes almost opaque under light illumination.
A polarisation reconfigurable circular polarised (CP) antenna for GPS application is designed and built using four photoconductive switches. By controlling the ON/OFF state of each of the four photoconductive switches on patch antenna, the polarisation of antenna can be switched from linear (LP) to CP, and from left hand CP (LHCP) to right hand CP (RHCP).
In this paper, an optically controlled millimeter-wave frequency selective surface using high resistivity silicon as tunable substrate is designed and tested. It is shown from measured results, the transmission performance of FSS at resonant frequency is tuned from −1.02dB to −16dB by light illumination. The photoconductive characteristic of silicon in millimeter wave region is studied. It is shown...
The Compact Antenna Test Range (CATR), which generates a pseudo-plane wave in a very short distance, is commonly employed to measure electrically large aperture antennas for the applications in space remote sensing and radio astronomy. With the increasing operating frequencies, the design of a CATR becomes a technical challenge. This paper presents the designs of two tri-reflector CATRs operating...
Active Frequency Selective Surface (FSS) with tunable response has been the focus of many researches. In this work, a new optically controlled approach which exploits variable dielectric property of organic semiconductor under the optical illumination is studied. P3HT and PTAA which are two potential organic polymers with tunable dielectric properties under optical illumination are investigated in...
Dichroics are key components in the design of quasioptical networks.However, there are many practical issues in designing and fabricating these components. This article presents the design and uncertainty analysis of a dichroic being operated in a two‐channel multireflector quasioptical network. The dichroic is designed to work as a frequency filter, which transmits at 54 GHz and reflects at 89 GHz...
With the current and future requirements of microwave and millimetric wave instrumentation, particularly the quasi-optical systems, there has been considerable research effort into low loss dichroics worldwide. This paper presents the design and experimental testing of a dichroic operating in a two-channel multi-reflector quasi-optical network (QON). The dichroic plate is designed to work as a frequency...
The grid would see the countless mobile devices becoming the most important users. However, the bottleneck is still at the last mile from the backbone to these mobile terminals where wireless environment places limitations on the rate and amount of communication. Currently, point-to-multipoint (PTM) communication is an effective solution to this limitation. This paper developed a new PTM mechanism...
Description logic based semantic query needs complete information from sources of knowledge where available information is often incomplete. To solve such incomplete reasoning problem, this paper embedded default logic into the description logic knowledge base, meanwhile prioritized the default rules, which preferred more specific default rules over more general ones. Then, an original incomplete...
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