Measurement of a CMOS negative inductor for wideband non-foster metamaterials

There is increasing interest in impedance-matching methods that use non-Foster circuits to provide wideband operation in a variety of microwave devices such as antennas and metamaterials. In addition, many of these prior non-Foster circuits employ bipolar negative impedance converter designs, and it is advantageous to move such designs into CMOS. Therefore, the present work provides new measured results building upon an earlier proposed design of a negative inductor in a 0.5 micron CMOS process. The proposed circuit eliminates a resistor from a common negative impedance converter topology, and the prototype performs well at high frequency. Measured results show a low-frequency inductance of -95 nH falling to -85 nH at 750 MHz and -63 nH at 1 GHz. Finally, simulation results are presented for the performance of the circuit in a metamaterial application.