Phase shifting holography for THz near-field/far-field prediction

With a view to extending techniques for THz antenna near-field/far-field prediction, this communication derives general analytic expressions for calibrated phase shifting holography (PSH) and introduces a new 120° three-step PSH method that avoids switching off the reference field and has symmetrical performance over the entire complex plane, providing spurious free far-field prediction. Numerical tests with simulated near-field patterns at 372GHz confirm the convenience of the method and give an indication of the precision required for the phase shifts.