A Christmas Tree-Shaped Quadband Compact Antenna with Triple Slots for Various Wireless Technologies

A compact, coplanar waveguide (CPW)-fed multiband antenna is developed and analyzed in this paper for quad-band applications. Christmas tree-like monopole antennae with three symmetric slots are designed on a low-cost FR4 epoxy substrate with the overall dimensions of 0.312 lambda(1 )x 0.364 lambda(1 )x 0.0083 lambda(1) where lambda(1) is the wavelength corresponding to the lower cut-off frequency. Three rectangular-shaped slots of different dimensions are etched on the three triangular-shaped stacked patches to enhance the current carrying path due to which the proposed antenna resonates at the required frequency bands. Different antenna parameters such as reflection coefficient (S-11), gain, radiation efficiency, surface current, radiation pattern, group delay and magnitude response of transfer function (S-21) are analyzed for inspecting the antenna performance. The quad-band antenna offers measured bandwidths of 3.1-3.9 GHz (22.86%), 5.46-5.98 GHz (9.1%) 9.76-11.74 GHz (18.42%) and 17.55-19.25 GHz (9.24%). The antenna shows nearly omnidirectional radiation patterns in all resonating bands with the highest gain of 4.5 dBi and measured radiation efficiency greater than 70% in all the bands. The antenna also offers stable group delay response and linear S-21 response in its operational spectrums. All these characteristics ensure the antenna's applicability in IEEE 802.16 WiMAX band, 5.5 GHz Wi-Fi band, 5.8 GHz ISM band, terrestrial broadband, radiolocation and earth explorer satellite applications.