A Wideband Wide-Strip Dipole Antenna for Circularly Polarized Wave Operations

Abstract

Abstract-A thin dipole antenna is a well-known antenna with linearly polarized wave operation. In this work, a wide-strip dipole antenna is proposed for circularly polarized wave operations. To obtain circularly polarized (CP) wave operations, there are two conditions to be satisfied. One is that the antenna must have two degenerated orthogonal modes with different resonant frequencies. The other is that the phase difference of two orthogonal modes is 90 degrees. To match the first condition, the slab width W is tuned to generate current distributions directed in two different directions. In addition, the second condition is matched by asymmetric feeding point by adjusting the overlapped square width C. The parametric study is completed by the Ansoft HFSS simulator. Simulated results reveal that the CP wave is mainly influenced by the slab width W . The influences of the parameters C and d on the performances of the proposed antenna are also investigated in this paper. Taking −8 dB as reference, there are two working bands for this proposed antenna and the measured center frequencies are 0.66 GHz and 2.04 GHz, respectively, and the corresponding bandwidths are 0.27 GHz (40%) and 1.78 GHz (87%), respectively. In addition, the measured center frequencies and bandwidths of the axial ratio are 1.94 GHz and 0.53 GHz (27%), respectively.Corresponding author: L.-P. Chi (cp531220@ms23.hinet.net). 70Chi et al.

A Two-Port Antenna for Wireless-Powered Uwb-Rfid Tags

“…Meanwhile, the circular polarization can also be excited by a so-called perturbation segment, like a widened L-type along the diagonal line of the square slot of antenna [11], a crisscross patch with proper dimensions embedded in the square slot [12], and a rectangular slot with 45 o on the radiating patch [13]. However, the axial ratio bandwidths are not wide enough, only 27% [10], 17% [11], 12.4% [12], and 7.1% [13], respectively. On the contrary, dual-fed provides the possibility to obtain wider axial ratio bandwidth, but it requires an external polarizer like power splitter or hybrid coupler.…”

“…Circular polarization can be generated under this condition: two orthogonal and linearly polarized modes with equal amplitude but with 90 o phase difference. There are mainly two kinds, i.e., the single-fed [10][11][12][13] and dualfed [14,15]. For example, in [10], by increasing the arm width of Figure 2.…”

“…There are mainly two kinds, i.e., the single-fed [10][11][12][13] and dualfed [14,15]. For example, in [10], by increasing the arm width of Figure 2. Block diagram of the wireless-powered UWB-RFID tags with different antenna topologies: (a) two separate antennas in [7,8], and (b) the proposed two-port antenna.…”

Broadband Single-Fed Single-Patch Circularly Polarized Microstrip Antenna

“…In the past decades, microstrip patch antenna technique has been developed rapidly [1][2][3][4][5][6]. However, the design of a broadband circularly polarized patch antenna that uses a single feed has long been a challenging problem, as compared to the design of linearly polarized (LP) and the dual-fed circularly polarized (CP) patch antennas [7,8].…”

“…However, the design of a broadband circularly polarized patch antenna that uses a single feed has long been a challenging problem, as compared to the design of linearly polarized (LP) and the dual-fed circularly polarized (CP) patch antennas [7,8]. Especially, the single-fed single-patch CP antenna has inherently narrow impedance and axial ratio (AR) bandwidths of 1%-2% [9,10].…”