Broadband and High-Gain Microstrip Patch Antenna Loaded With Parasitic Mushroom-Type Structure

This letter presents a novel broadband microstrip patch antenna with a simple geometry. Two parasitic mushroom-type arrays are incorporated along with the two radiating edges of a main radiating patch. Firstly, thanks to the mushroom-type structure, a new resonant mode, characterized as quasi-TM30 mode, is generated. Besides, the main radiating patch produces the original TM10mode. Thus, wideband performance is realized based on the two combined modes. Secondly, the current distributions on those metal patches are nearly uniform so that high gains are achieved over the entire operating bandwidth. Measured results indicate that the enhanced impedance bandwidth is from 11.9 to 18.2 GHz, which covers the whole Ku-band. Meanwhile, a nearly constant peak-radiating gain between 10 and 10.5 dBi at broadside radiation is obtained. The proposed antenna maintains the advantages of wide bandwidth, ease of fabrication, flat and high gains, and a low profile less than $\lambda_{0}/13$ thickness substrate.