A Low-Profile Compact Circular Patch Antenna with Monopole-like Radiation Pattern

Excitation of TM 01 mode in planar circular patch antenna exhibit monopole-like radiation pattern and yet have a low-profile in terms of the vertical height of the antenna. Such an antenna is useful for smart IoT/wireless sensor network applications. The design of a narrow-band antenna operating in the 2.4GHz ISM band that is also compact in the lateral dimension and made with a single layer of substrate is presented in this paper. Due to the resonant nature of the radiating element, low-loss substrate such as RO5880 is needed to achieve higher realized gain. The measured antenna performance in terms of both the reflection coefficient and the radiation pattern are presented. Since no air layers are used in the design, conventional printed circuit board fabrication is possible to realize the antenna and hence can be easily integrated with the sensor electronics as demanded by the application.