Patent ID: 8462065

Claim:
An antenna apparatus including: a first antenna element; a second antenna element; and a branch circuit to which the first antenna element and the second antenna element are coupled via respectively separate transmission lines; wherein a delay process is conducted on one of the transmission lines by modifying the lengths of the transmission line coupling the first antenna element to the branch circuit and the transmission line coupling the second antenna element to the branch circuit, thereby adjusting the input impedance and/or phase of the first and second antenna elements such that wider band characteristics than the antenna characteristics of the first and second antenna elements individually are configured, when the distance between a site where the absolute value is maximized over a current distribution of the first antenna element and a site where the absolute value is maximized over a current distribution of the second antenna element is taken to be the antenna-to-antenna distance, and when the length of a delay line produced due to a difference in the lengths of the two transmission lines is taken to be the delay line distance, the absolute value of the difference between the antenna-to-antenna distance and the delay line distance is made equal to an integer multiple, equal to or greater than 0, of the wavelength of a frequency at which transmitting or receiving is conducted in the antenna apparatus, and the sum of the antenna-to-antenna distance and the delay line distance is made equal to an integer multiple, equal to or greater than 1, of the wavelength of a near-center frequency at which transmitting or receiving is conducted in the antenna apparatus.