Folded dipole antenna with feed line (FDAFL) whose relative bandwidth is 65% (VSWR≤3) has been reported as a wideband planar antenna for a small terminal. However, this antenna is constructed outside of the ground plane (50×80mm2) by 12mm. In this study, we analyze the antenna configurations of FDAFL in 3D so that the antenna does not protrude from the ground plane as much as possible. Two different 3D antenna models derived from FDAFL are investigated. The first model is folded over the ground plane, and the second one is folded outside of the ground plane. The relative bandwidth, the VSWR characteristics and radiation patterns are studied. As a result, it is confirmed that antenna prominence could be reduced and broadband characteristics over 74% and 83% are obtained by the 3D models, respectively, which are wider than the bandwidth of conventional 2D model. Thus, FDAFL could be used in both 2D and 3D for a small terminal.

This paper proposes the design to reduce the number of fed elements by replacing with parasitic elements in an array antenna. The study depends on the analysis of electromagnetic wave fields in consideration of the coupling between the half-wavelength dipoles. The case of 2 fed elements and 2 parasitic elements is considered as a unit cell to form the total array. After optimizing the element arrangement, the antenna gain can match that of the equivalent 4-fed element case. Feeding networks in a high power radiating system are analyzed in terms of the length and matching of feed lines, and the arrangement of amplifiers.

A dual-offset microstrip-fed slot antenna having large bandwidth studied in this paper. The proposed antenna is analyzed by the Finite Difference Time Domain (FDTD) method. In this case, two offsets and other design parameters of the antenna lead to the good impedance matching over a wide frequency band. The experimental bandwidth is approximately 1.587 octave (-10 dB S11). And the experimented data for the impedance loci, the radiation patterns, and gain of the antenna are also described. The measured results are relatively in good agreement with the FDTD results.