Circuit Model of a Receiving Leaky Line Antenna (LLA)

A circuit model is proposed to analyze the receiving performance of a leaky line antenna (LLA), i.e., a coaxial cable with aperture slots in the shield. The LLA is assumed to be a series connection of circuit multiport networks equivalent to leaky and nonleaky cable sections. The quasi-TEM mode is assumed to be the dominant propagation mode inside the cable permitting the simulation of the nonleaky sections by the model of multiconductor transmission line with distributed voltage and current sources. The cable leaky sections with slots in the shield are modeled by equivalent multiport networks, whose lumped circuit parameters are extracted numerically by an electromagnetic (EM) field solver. The resulting circuit is given by a series cascade of multiport networks and is analyzed in the frequency domain. The LLA performance calculated for different test configurations is validated by comparison with measurements and with simulations carried out by a full-wave EM code. The proposed circuit procedure is an efficient tool for simple design and analysis of LLA configurations.