Novel series divider for antenna arrays with arbitrary element spacing based on a composite right/left-handed transmission line

In this paper, a novel feeding method for equal amplitude and phase excitation of each antenna with arbitrary spacing is presented. It is demonstrated that equal excitation can be accomplished without regards to the element spacing. This series feed network is based on the infinite wavelength property of the composite right/left-handed (CRLH) transmission line (TL). At a particular resonance frequency, the CRLH TL is able to support a wave with an infinite wavelength. Consequently, the magnitude and phase along the TL are a constant at this infinite wavelength frequency. To demonstrate the novel series feed network, a 5-port series feed network based on the infinite wavelength property of the CRLH TL is first constructed and tested. Then, identical quasi-Yagi antennas are connected to each port of the network and radiation patterns of the antenna array are measured to demonstrate the authors' claims.