Broadband microstrip antenna with a hairpin bandpass filter

A new design for a broadband microstrip antenna is proposed, the working band of which is broadened using a bandpass filter based on two hairpin resonators electromagnetically coupled with a half-wave radiating resonator with a rectangular strip conductor. It is shown that the operating frequency range of this antenna is significantly extended as compared with that of analogous antennas, while its directivity and polarization diagrams remain highly stable within this range, which makes this design promising for applications. Operability of the antenna is demonstrated using its operating prototype. The measured characteristics of the antenna prototype agree well with the calculated data.