1.1 Microstrip fed monopole. The planar monopole antenna has a simple structure and a nearly omnidirectional radiation pattern, and is widely used in communication.
1.2 Coplanar waveguide-fed monopole antenna. One of its features is the use of coplanar waveguide feeds. Coplanar waveguides have two major advantages over traditional microstrip lines: high frequency low offset and wide impedance bandwidth. Another feature is that the radiating element uses a hexagonal patch, and the hexagon also has the inherent advantage of broadband characteristics compared to other rectangles, squares, and triangles. The entire antenna feed portion is short-circuited on the lower surface of the grounded coplanar waveguide, so that a short circuit is formed between the upper and lower layers, thereby preventing the generation of a parasitic mode, and the number of holes can also change the input impedance of the antenna.
