CMOS Antenna Tuning Unit for 2.4 GHz ISM Band

Antenna matching is improved with adaptive 0.35 $\boldsymbol{\mu}\mathbf{m}$ CMOS circuits based on switched shunt capacitors arranged in capacitor banks and external series inductors. The simulated circuits are optimized for the ISM 2.4 GHz band. The circuits provide a VSWR ≤ 2 match for every impedance with VSWR ≤ 5. There is a 1 dB power loss for a perfect 50 Ω → 50 Ω transformation, a break-even point at VSWR = 1.5, and a 3dB increase in delivered power for VSWR = 4.3.