Compensation of electric cross-field response in shielded loop probe

The singly-loaded shielded loop probe is investigated with respect to its sensitivity to electric fields. A standing-wave open microstrip transmission line cell is used to measure the response of a loop probe of 1% wavelength diameter to the magnetic field normal to the loop plane and to the electric field along its symmetry axis and along its cross direction. The response to the electric cross-field is shown to exhibit the characteristic of a short electric dipole, which has inspired a compensation technique using an additional wire dipole cross-connected over the shield gap. Experimental results of the compensation technique are presented, which show effective reduction of the E-field pick-up by 10-15 dB while maintaining the useful properties of the H-field probe.