  In this work, a parametric up-converter amplifier is introduced as a wideband
impedance matching network for receiving electrically small antennas. Chu's
limit restricts the minimum Q-factor of unloaded small antennas; however, the
practical bandwidth of small antennas is defined by their loaded Q-factor. By
connecting a small antenna to an amplifier with a real input impedance several
times greater than the radiation resistance of the antenna, we propose
increasing the return loss to reduce the loaded Q-factor and increase the
bandwidth as a result of the Bode-Fano theorem. In addition, a parametric
amplifier is used because, in comparison with transistor amplifiers, it offers
low noise characteristics. The gain of the low noise parametric amplifier
compensates for the loss due to the imposed mismatch. Our simulation result
shows bandwidth improvements up to 32 times can be accomplished by trading 2 dB
of noise figure compare to 15 dB suggested by Chu's limit for a lossy antenna.
