Suppression of Cross-Polarization of the Microstrip Integrated Balun-Fed Printed Dipole Antenna

Abstract EN

The high cross-polarization of the microstrip integrated balun-fed printed dipole antenna cannot meet the demands of many engineering applications.

This kind of antennas has high cross-polarization levels (about −20 dB).

And we find that the high cross-polarization radiation is mainly produced by the microstrip integrated balun rather than the dipole itself.

The very limited method to lower the cross-polarization level of this kind of antennas is to reduce the substrate thickness.

In this paper, to improve the low cross-polarized performance, firstly, an equivalent model is presented to analyze the cross-polarization radiation.

Secondly, a novel structure with low cross-polarization is proposed.

The microstrip integrated balun is enclosed by a center slotted cavity.

The E-field of the microstrip integrated balun is transformed parallel to the dipole arms by the slot, so the radiation of the cross-polarized component is suppressed.

Measured results show that this structure can achieve a bandwidth wider than 40% while reducing the cross-polarization level to less than −35 dB within the frequency band.