Compact Omni-Directional 2.4 GHz Antenna for ISM Band Applications

This work proposes the design of a compact omni-directional antenna (COA) for small bandwidths. The antenna that is being suggested is small, measuring just $27 \times 27\times 1.6$ mm3, and has a limited fractional bandwidth of 4.16 %. The antenna operates in the impedance operating frequency band of 2.35-2.45 GHz (100 MHz), with an impedance matching well below SII ≤ -10 dB, and a reasonable gain of 2.35 dB. In the H-plane, the suggested antenna offers a compact omni-directional radiation pattern, and in the E-plane, a bidirectional radiation pattern. A defective ground structure (DGS) is used to achieve miniaturization. This antenna's omnidirectional radiation pattern, reasonable gain, and compact size make it a good fit for wearable devices, cordless phones, gaming consoles, and other consumer electronics that use the 2.4 GHz frequency for wireless communication, including Industrial, Scientific, and Medical (ISM) devices.