SQUARE PATCH ANTENNA

PROBLEM TO BE SOLVED: To provide a square patch antenna capable of obtaining excellent specific bandwidth, while attaining miniaturization.SOLUTION: A coaxial connector 12 is provided as a plug for electric supply, under a conductor plate 11 formed in a shape of a square, and a square patch antenna element 13 is provided over the conductor plate 11 at a prescribed interval. That is, the patch antenna element 13 with the length of one side of about λ/4 is provided over the conductor plate via an air layer whose specific dielectric constant is about "1". The patch antenna element 13 is provided with a square window 14 at the center thereof; the window 14 part is provided with a first feed point 15 and is connected to an inner side of the patch antenna element 13 via a λ/4-impedance matching box 16, and the impedance of the first feed point 15 is set, for example, to the value of 50 Ω. A center conductor 12a of the coaxial connector 12 is connected to the first feed point 15 to feed power.