Circularly polarized dielectric resonator‐loaded circular microstrip patch antennas for WLAN 2.4 GHz applications

Abstract

Moreover, we would like to note that the folded antenna has much smaller size than the unfolded antenna, in addition to the bandwidth improvement in the DCS band.An absolute gain including the return loss and radiation efficiency was measured. The measured radiation patterns for the proposed antenna at 1 and 2 GHz are presented in Figure 6. The radiation patterns of H, E1, and E2 planes were measured in the x-y, z-x, and y-z planes, respectively. In the x-y plane, the radiation pattern at 1 GHz had quite good omni-directional characteristics. The radiation pattern gets more directional in the high-order resonant 2 GHz band. For the GSM and DCS bands, maximum absolute antenna gains (G 0abs ) were Ϫ0.05 and Ϫ0.13 dBi, respectively. These radiation patterns show that the proposed antenna had a good radiation efficiency. CONCLUSIONA dual-band small chip antenna was designed to satisfy requirements for operation in the GSM and DCS bands. The impedance bandwidth and resonant frequency of each band was controlled by the intercoupling capacitance of the metallic structure. The intercoupling capacitance was created by folding a metallic structure. The resonant frequencies were nonuniformly shifted due to the intercoupling capacitance. This property was very useful in controlling the resonance frequencies and their corresponding bandwidths. The simulated and measured results show that the proposed antenna satisfies the requirements for both GSM and DCS bands simultaneously. This resonanceshift effect caused by the folding intercoupling capacitance can be usefully exploited in designing a multiband antenna with high-order resonance phenomena. printed monopole, Electron Lett 28 (1992), 1326 -1327. 4. M. Makimoto and S. Yanashita, Microwave resonator and filters for wireless communication, Springer Verlag, New York, 2000, pp. 84 -87. 5. C.A. Balanis, Antenna theory and analysis and design, Wiley, New York, 2005, pp. 177-217. ABSTRACT: Dielectric resonator-loaded circular microstrip patch antennas can be used as an alternative way to generate circular polarization. The dielectric resonator is placed on the edge of the circular microstrip patch antenna to result both strong coupling effect and two degenerated orthogonal modes. Then, we choose the feeding point, the placed position and size of DR, and the height of antenna as key tuning parameters; both wide circular polarization and impedance matching are achieved. Application is given for WLAN 2.4 GHz band. Both simulated and measured data are matched well. Measured results show that the center frequency is at 2.45 GHz. The impedance bandwidth is 19.2%. Besides, the axial ratio bandwidth is 3.7% (2.39 -2.48 GHz). The radiation patterns are broadside radiations and high antenna gain of 8.6 dBic is achieved.

Circularly Polarized Dielectric Resonator Antennas: Design and Developments

“…In this CP design [61], both strong coupling effect and two orthogonal degenerated modes are achieved by placing the DR element on the edge of the circular microstrip patch antenna as shown in Fig. 22.…”

“…A special coupling slot has been used to excite the DRA for circular polarization such as a cylindrical DRA excited by, a cross slot of unequal length [12], a perturbed annular slot, a C-shaped slot [16], an asymmetrical U-slot [19], a hemispherical DRA excited by a shorted annular slot [21], a cross-slot-coupled hemi-ellipsoidal DRA [25], an elliptical dielectric ring resonator is excited by an aperture-coupled microstrip patch with reversed T-shaped slot [64], a rectangular stair shaped DRA excited by a narrow rectangular slot and rotated 45°with respect to the sides of the DRA [26], a cylindrical DRA fed by four sequentially rotated slots [35]. To excite the CP DRA, the use of a conformal strip has been also reported such as cylindrical DRA excited by two conformal strips of unequal lengths [13], a rectangular DRA fed by two vertical strips in phase quadrature for a dual-mode operation [32], a metallic strip has been printed diagonally on the top face of the square DRA and fed by a slot [15], a conducting strip loaded cylindrical DRA [24], a quadruple strip feed cylindrical DRA utilizing a pair of 90°hybrid couplers [30], a dielectric resonator-loaded circular microstrip patch antennas are also studied [61]. A loading patch on the DRA can also generate the circular polarization such as a lowprofile square DRA with a rectangular loading patch having a suitable aspect ratio [14], slot-coupled cylindrical DRA with a parasitic patch [17], conformal-strip excited hemispherical DRA with a parasitic patch [20], aperture-coupled hemispherical DRA with a parasitic patch has been investigated [60].…”

“…It is used for WLAN 2.4 GHz band application. The CP radiation exhibits an axial ratio bandwidth of 3.7 % (2.39-2.48 GHz)[61].…”

Wideband circularly polarized square dielectric resonator antenna for WLAN/WiMAX applications

“…Therefore, the leakage effect from the patch edge characterizes the radiation from the rectangular patch. The strong coupling effect can be generated only DR across the rectangular patch edge . To control the coupling between the square DR and the edge of the rectangular patch, the overlapping width W 1 and W 2 are the main factor.…”

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

“…The other is that the phase difference of two orthogonal modes is 90 degrees. The often utilized technique to generate CP wave in the microstrip antenna is feeding asymmetrically in the microstrip patch to generate two degenerated modes and to complete impedance matching [11][12][13][14][15][16][17][18][19][20]. However, it is impossible to generate a circularly polarized wave in a single dipole antenna because only z-directed current distribution exists on the thin cylindrical conductor.…”