Patent ID: 8102330

Claim:
An antenna system, comprising: a first radiating element; a first feed network, including: a pair of antenna element ports interconnected to the first radiating element; an input/output port; an isolation port resistor, wherein the first feed network provides a first signal path length between the input/output port of the first feed network and a first antenna element port of the pair of antenna element ports of the first feed network, wherein the first feed network provides a second signal path length between the input/output port of the first feed network and a second antenna element port of the pair of antenna element ports of the first feed network, and wherein for a signal having a first wavelength the first signal path length provided by the first feed network differs from the second signal path length provided by the first feed network by from 80 electrical degrees to 100 electrical degrees; a second radiating element spaced apart from and superimposed over the first radiating element; a second feed network, including: a pair of antenna element ports interconnected to the second radiating element; an input/output port; an isolation port resistor, wherein the second feed network provides a first signal path length between the input/output port of the second feed network and a first antenna element port of the pair of antenna element ports of the second feed network, wherein the second feed network provides a second signal path length between the input/output port of the second feed network and a second antenna element port of the pair of antenna element ports of the second feed network, wherein for a signal having the first wavelength, the first signal path length provided by the second feed network differs from the second signal path length provided by the second feed network by from 80 electrical degrees to 100 electrical degrees, and wherein a distance between the first antenna element port of the pair of antenna element ports of the first feed network and the first antenna element port of the pair of antenna element ports of the second feed network is equal to a distance between the second antenna element port of the pair of antenna element ports of the first feed network and the second antenna element port of the pair of antenna element ports of the second feed network.