Wide frequency reconfigurability on a miniature omnidirectional antenna combining variable capacitance and inductance

The goal of this study is to present a wide frequency agility technique obtained on a miniature omnidirectional antenna using a combination of variable capacitance and inductance. The structure is a compact shorted microstrip omnidirectional antenna which has already been miniaturized by a slot loading technique. In order to fight frequency bandwidth reduction associated to antenna miniaturization and to fulfil modern telecommunication standard requirements which operate over wide frequency bands, two active components are added to the structure so as to obtain a wide frequency agility. Based on this technique, an electronically tunable antenna with a frequency range of 0.940-1.41GHz is designed with typical dimensions (width x length x height) of λ₀/11 × λ₀/11 × λ₀/63 at the lowest operating frequency (λ₀ being the free space operating wavelength).