| 摘要 |
Disclosed is a dipole array antenna that is particularly useful at UHF and microwave frequencies. In an exemplary embodiment, the antenna is comprised of two dipole radiating elements-a driven dipole of length L1 and an unfed element closely spaced from the driven element, of length L2. The ratio L1/L2 is at least 1.1, and may be optimally set at about 1.3. Preferably, at a reference frequency in which VSWR is minimum, the length L2 of the unfed element is less than 0.45 wavelengths, and optimally, is in the range of 0.39-0.42 wavelengths, with dipole spacing in the range of 0.07 to 0.11 wavelengths at the reference frequency. Advantageously, the antenna exhibits a low VSWR in a 50 ohm system over an operating frequency band, whereby a matching network can be avoided. High gain and front-to-back ratio is also realizable while antenna size is kept small.
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