1 Effects of Quadratic Phase Error

2 Patterns at different range If the antenna is impedance matched, how can we check the Antenna is in radiation? Antenna operation is usually in Fraunhofer region Near field region is suitable for NF measurement, why?

3 Far Field Range Phase error of far field range For maximum of Quadratic phase error is when

4 Quadratic phase error is at Quadratic phase error is at Quadratic phase error is at Patterns due to quadratic phase error Effect of Quadratic Phase Error 1.Gain is reduced 2.Wider the beamwidth 3.Higher the first SLL 4.Higher the first null value

5 Definition of Quiet Zone 1. The zone area (length, width, height) which antenna or target under test 2. Performance of E field on the wavefront E field with taper and ripple in both amplitude and phase 3. For ideal plane wave Amplitude: taper 0 db, ripple 0 db Phase: taper 0 degree, ripple 0 degree 4. The larger the amplitude/phase error in the wavefront, the larger the error for the result of pattern measurement

6 Anechoic chambers and corresponding side-wall reflections

7 Antenna-range measuring system

8 Near- and far-field phase pattern measurements

9 Single frequency measuring system

10 Swept frequency measuring system

11 Polarization measuring system

12 Polarization amplitude and phase measurements