A phased array antenna includes a substrate, and an array of dipole antenna elements on the substrate. An estimated VTC conversion angle VTCNFS is calculated in accordance with a sensed VTC conversion angle VTCNOW. A darkfield illuminator may be advantageously employed with the LED-assisted magnifying device when gemstones are being inspected. A sleep mode detector may be provided to configure the multiplexer to select the power control vector and to operate the clock generator to clock the power control vector into the scan chain elements when a sleep mode of the circuit is detected.