Equivalent circuit modeling of chassis-antenna with two coupling elements

The paper proposes two new equivalent circuits which can be used when analyzing chassis-antennas with one or two coupling elements. The new equivalent circuit for the chassis-antenna, with a single coupling element, models the impedance of the antenna better than was previously possible. For the chassis-antenna with two coupling elements, the equivalent circuit model become more complex and an impedance inverter has been used to represent the coupling between two closely separate coupling elements.