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Seven element wideband planar log-periodic antenna for TVWS base station

This paper presents design and simulation of a wide band antenna for base station in the TV White Space (TVWS) spectrum band operating between 470 MHz-700 MHz. Concept of printed Log Periodic Dipole Array (LPDA), which provides wide bandwidth, has been used to realize wide band antenna. The antenna elements are printed on low cost FR4 substrate with εr = 4.4 and tan δ = 0.02. These elements are printed alternatively on both side of the substrate. Total volume of the antenna is 303 × 162.3 × 1.6 mm3. To reduce the size, scaling factor (τ) for this design is considered as 0.89 and the relative spacing (σ) is chosen as 0.054. The antenna is fed at the base of smallest element. The antenna shows an impedance bandwidth for VSWR ≤ 2 in the frequency range of 470 MHz–700 MHz. The gain of this antenna is between 5.3 dB to 6.5 dB in the entire band of operation. The radiation pattern shows end fire behavior with uniform radiation pattern in both E and H-planes with maximum front to back lobe ratio (F/B) of 30 dB.