Experimental demonstration of the "apparent wavelength"

In this paper, an experimental demonstration of the "apparent wavelength" using microwaves incident on a plane conductive surface obliquely, with the electric field polarization parallel to a reflecting plane, is presented. Standing wave measurements were obtained by utilizing the interaction between the transmitting and the receiving rectangular horn antennas using the receiving horn antenna as a probe. This technique demonstrates to the students that the wavelength along the normal, the "apparent wavelength" is longer than the wavelength of the free-space incident or reflected waves and is in agreement with the theory. Finally, the proposed technique demonstrates high sensitivity and accuracy for tutorial demonstrations of standing wave pattern measurements despite the large cross-section of the receiving antenna.