Short-wave Ultra-short Wave Broadband Miniaturized Antenna And Matching Network

In modern communication technologies, with the development of spread-spectrumand frequency-hopped communication technique, multi-frequencies, multi-functionand wide frequency-hopped broadcasting stations are used at large. At the same time,the rate of frequency-hopped becomes more and more rapid, and the range becomesmore and more wide. On the other hand, the problem of electromagnetic interferencebetween electronic equipments appears and cannot be ignored because of the greatquantity of communication equipments and antennas on flats. If use a antenna that cancover with the whole frequency range of communications on flats, we can decreasethe electromagnetic interference problem between equipments greatly. Because oflow frequency and long wavelength, HF/VHF antennas have to be made big sizeconventionally, while big size can't satisfied limited space of flats. So the HF/VHFbroadband omnidirectional small-size antenna for modern communication becomesmore and more important and need to be researched as soon as possible.In this paper, we introduce and summarize the technique of HF/VHF broadbandantennas at present, then, we focus on the research and measurement of the newdiscone antenna, types of discage antennas etc. Especially, discage antennas havesmall electrical size. Discage antennas combine the structure of discone antenna andcone-shape monopole antenna, and make use of ultra-wide-band twin-feed matchingsets. The sets adopt gradual change cavum and equivalent extend structure, and havetwo feed system. All these characteristics can extend frequency band , reduce antennaelectric size and improve impedance characteristics. In order to miniaturization ofantenna, impedance complete compensate and matching optimization of electricallysmall antenna are brought forward, and this method is applied to the discage antennas.On the basis of the characteristics of water, in this paper, the monopole and theconical monopole antenna loaded by water are researched by experiment. Indicated bythe experiment data of impedance and radiation characteristics, the resonancefrequency of the monopole antenna loaded by water declined clearly and theresonance frequency band of the conical monopole antenna loaded by water go down...