A Novel RF Power Detector Based on Positive and Negative Thermistors Using Standard CMOS Technology

In this letter, a novel RF power detector (PD) that operates at X-band range is presented using standard 0.18-
$\mu \text{m}$
RF Complementary Metal Oxide Semiconductor (CMOS) technology. The proposed RF PD is mainly composed of a coplanar waveguide (CPW), two matched resistive loads and a Wheatstone full-bridge structure with positive and negative thermistors. Experimental results demonstrate that the device shows excellent RF-DC linearity, high sensitivity and stable impedance matching characteristics. In the power regions of [1, 200] mW, the measured sensitivities are
$169.6~\mu \text{V}$
/mW,
$162.8~\mu \text{V}$
/mW, and 154.3
$\mu \text{V}$
/mW, at 8, 10, and 12 GHz, respectively. And the measured return loss is less than -19.1 dB at 8-12GHz. The total chip area is
${0.26}\times {0.4}$
mm
²
, including all pads. Moreover, the absence of post-CMOS micromachining required for the RF PD fabrication with respect to a standard CMOS process would have a significant economic advantage as a low-cost PD with RF ICs.