The Force on an Antenna Array
نویسندگان
چکیده
Antennas radiate (vector) momentum as well as energy, but if the radiation pattern is symmetric, the total radiated momentum is zero. Consider a simple antenna array that consists of two short linear dipole antennas whose centers are λ/4 apart and whose conductors point along the line of centers of the antennas. If the two antennas are excited with a 90◦ phase difference, deduce the asymmetric radiation pattern and the time-average rate of momentum d 〈P〉 /dt, that is radiated. The antenna experiences a time-average reaction force 〈F〉 = −d 〈P〉 /dt.
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