COMPARATIVE ERROR ANALYSIS OF DIFFERENT NEAR FIELD PROBE ARRANGEMENTS IN THE PLANE OF OPEN ENDED WAVEGUIDE RADIATOR

The Moment Method is used to evaluate the inaccuracy caused by different dipole probe arrangements in the plane of the open-ended waveguide aperture. The radiated magnetic field and internally scattered wave at the plane of the opening is estimated by the plane wave spectrum and modal expansion approach respectively. The fields dispersed due to induced current on the dipoles have also been calculated by means of the theory of vector potentials. The boundary conditions are all together forcedon the plane of the radiator opening and on the axis of the sensors by seeing numerous reflections between the radiator and sensors. The boundary condition on the plane of the radiator opening is the tangential component of the magnetic field, both within and outside the radiator should be identical. Calculation has been accomplished to equate the relative sampled sensor voltage pattern to the relative sampled electric field (without probe) pattern in the scan plane with different arrangement of the dipole and error induced by the dipoles are compared.