초록 ▼

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 L

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.

대표청구항 ▼

[ What is claimed is:] [15.] A directional dipole array antenna, comprising:a driven dipole of length L1 driven by a 50 ohm transmission line feed for radiating at a frequency f.sub.C ; andan unfed dipole of length L2 substantially parallel to the driven dipole, and closely spaced therefrom to be ex

[ What is claimed is:] [15.] A directional dipole array antenna, comprising:a driven dipole of length L1 driven by a 50 ohm transmission line feed for radiating at a frequency f.sub.C ; andan unfed dipole of length L2 substantially parallel to the driven dipole, and closely spaced therefrom to be excited by near field coupling from the driven dipole,wherein only said driven and unfed dipoles are included in said array antenna, a length ratio L1/L2 is at least 1.1, L2 is less than 0.45 wavelengths at a frequency f.sub.C within an operating frequency band of the antenna and said dipole lengths being selected in conjunction with spacing between said dipoles such that said antenna is substantially matched to said 50 ohm transmission line feed over the operating band and radiates a directional beam at said frequency f.sub.C.