A new class of broadband antennas using complementary pair element groups

In the novel complementary pair element group (short: CPEG) a broadband impedance match is accomplished by feeding two antenna elements with complementary characteristics from one hybrid junction. This paper describes in detail two of the many possible realizations of this principle, the vertical dipole and folded dipole CPEG, and the endfire monopole CPEG, which is a near-optimum radiator for vertically polarized steerable arrays such as super-power HF transmitting arrays. However, the CPEG matching method allows not only the broadband operation of high-gain broadside reflector arrays, but is also extremely useful in a variety of other antennas. Examples are linearly and circularly polarized feeds for paraboloids and para-cylinders, endfire element groups in vertically polarized circular arrays, and stacked element groups in endfire arrays with non-uniform element spacing. Recommended applications include communications, high-quality broadcasting, air traffic control, radar, tracking, spectrum surveillance and radio astronomy. The CPEG concept is thus shown to be of universal impact on broadband antenna design, and in many cases to provide a more economical and more flexible solution than other existing broadband radiators.