| 摘要 |
<p>The assembly comprises three aerials which are arrangeD, in a straight line. The two outer elements (A1, A2) are active, whilst the middle element (P) is a passive reflector. The active elements are at a quarter wavelength distanc efrom the passive element. If the active elements are each supplied with HF signal of equal amplitude and phase a practically circular radiation field results. If the signals are in antiphase the radiation plot approximates to a figure eight. The advantage of the arrangement overs a single aerial is that for equal energy output the intensity of the electromagnetic field at all points has twice the value obtained with the single element.</p> |
