The Research And Design Of A Microstrip Antenna With Filtering Characteristics

The microstrip antennas with filter characteristics, which have both the antenna and filter function, are able to filter certain frequency band/bands without deteriorating the antenna performances at operational frequencies. Therefore, the filter design in the traditional design of those products can be removed and the energy attenuations between devices can be reduced as well. As a result, the microstrip antenna with filter characteristics shall meet the requirements of current technology developments and is the main trend of future development. For the hot topics such as band notched ultra-wideband (UWB) antenna and harmonic suppression antenna, related researches were carried out extensively and in detail. The major work of this paper including:Firstly, the background and significance of research on the microstrip antenna with filter characteristics (band notched UWB antenna and harmonic suppression antenna) are described. A brief introduction to such technology at home and abroad as well as the develop trends are given latter.Then, considering the specific application in UWB applications, a number of UWB antennas with different notch bands are presented and studied. General approaches of realizing notch bands are summarized. Three typically methods:etching slots and adding parasitic elements as well as etching slots/adding parasitic elements are studied by designing with the three means respectively. Finally, the measured results all showed similar results with the simulated data in the tests. These antennas can not only meet the relevant requirements (impedance matching band, radiation characteristics) of UWB communications, but also showing good band notched characteristics in certain interference frequency bands without any deterioration of UWB performances.Then followed, taking into account the widely exists and hazards of harmonic frequencies in the systems such as wireless communications and MPT, the microstrip antenna can filter the harmonic frequencies, that is the harmonic suppression antenna (HSA) are extensively studied. According to the differences of feeding ways, the HSAs fed by microstrip and coplanar waveguide are detailed design and researched respectively. Among them, the researches and designs of microstrip-fed HSAs are mostly focus on the miniaturization. Besides, a dual-band microstrip-fed HSA which can operate in the2.45GHz and5.8GHz bands is proposed for the first time. On the other hand, the research and design of CPW-fed HS As are mainly about miniaturization and broadband. And a general approach and the steps of design such CPW-fed HSAs are proposed.Lastly, both the summary and conclusions of the researches in this paper are presented. And considering the shortage of such researches, the future research directions are pointed out.