Bandwidth-extended dipole antenna based on composite right/left handed transmission line

To solve the problem of narrow bandwidth in electrically small antenna which employs periodic composite right/left-handed(CRLH) transmission line, a new type of electrically small dipole antenna using non-periodic CRLH transmission line is proposed. The model includes N units of various size LC ladder network cells. Staggered tuning is implemented to improve the antenna impedance matching and broaden the antenna bandwidth. A four units non-periodic CRLH dipole antenna is designed. The simulation and experiment show that when the length of the antenna is 0.135λ₀, 8.55% impedance bandwidth with |S₁₁|≤-10 dB can be achieved. The matching performance of the antenna is improved to a large extent.