Current Issue : July - September Volume : 2020 Issue Number : 3 Articles : 6 Articles
We investigate a circularly polarized (CP) transmission-line antenna composed of loop radiation elements, called a loop-line\nantenna. To enhance the CP wave bandwidth, an isolated loop radiation element is first analyzed using the method of moments. It\nis found that a CP wave bandwidth for a 3 dB axial-ratio criterion has a maximum value of 8%. On the basis of the analysis results,\nwe design the loop-line antenna. It is found that the antenna shows a CP wave bandwidth of 6%, which is twice as wide as that of a\nconventional loop-line antenna. The analysis results are verified with experimental ones. In addition, a condition for wideband CP\nradiation is discussed and found to be a composite radiation element consisting of two CP loops....
The cross-polarization isolation (CPI) is a key parameter to assess the dual-polarization\nantenna because the cross-polarization closely affects the antenna application. A polarization state\nconfiguration (PSC) approach is proposed to configure the polarization state of the polarimetric\nphased array radar antenna. Unlike the traditional fixed polarization states such as the linear\npolarization (LP) and the circular polarization (CP), the PSC method modulates the polarization\nstate of the radiated wave continuously. In addition, the optimal excitation magnitude and phase\nof the dual-polarization element is calculated, thereby maximizing the CPI. Most of the configured\npolarization state is the elliptical polarization (EP), and a lower cross-polarization level and higher\nCPI could be obtained. This method could expand the acceptable angle range when compared with\nthe LP and CP waves. Numerical simulations and comparisons are conducted to manifest the validity\nof the proposed method....
In this paper, a low-profile antenna is presented for wideband communication\napplications. The presented design consists of an I-shaped driven strip and a rectangular ground\nstrip with an open slot in the middle and a steeped lower portion. .............................
A single-layer waveguide slotted array antenna is proposed for W-band applications. To eliminate the alignment errors, all\nstructures including the radiation slots, radiation waveguides, and power divider network are realized in one layer based on the\nmilling process, and a planar metal plate is employed to cover the bottom..............................
This paper presents a new compact microstrip filtering antenna with modified shaped \nslots to improve the impedance bandwidth. The proposed microstrip filtering antenna consists of \nthree parts: the monopole radiating patch antenna; the Stepped Impedance Resonator (SIR) filter; \nand the feeding microstrip line.......................
This research proposes a compact elliptical ring antenna excited by a circular disc monopole (CDM) for ultra-wideband (UWB)\ncommunications. In the study, time- and frequency-domain pulse distortions of the antenna in the transmission mode were\ncharacterized by magnitude and phase of the antenna transfer function (Hrad). The results showed that the gain and magnitude of\nHrad in the boresight direction are sufficiently flat with linear phase response. The average antenna gain is 3.9 dBi over the UWB\nspectrum................................
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