A microwave imaging microscope and associated probe, or a read head. The probe or the read head includes a sensor unit with three fixed electrodes, preferably a stimulating electrode surrounding a sensing electrode and isolated by a grounded electrode. Circuitry couples the stimulating electrode to the probe signal variably selected in the range of 100 MHz to 100 GHz and couples the sensing electrode to a signal processor detecting in-phase and out-of-phase components of the current or voltage across the sensing electrode and the grounded electrode. A mechanical positioner moves the probe vertically towards the sample and scans it across the sample. The probe may be formed by semiconductor processing methods on a silicon chip.