Mathematical modeling and characteristic mode analysis for investigating the bandwidth and radiation pattern performance of an ACPW microstrip antenna

This paper introduces an innovative antenna configuration that incorporates multiple quarter-wavelength transmission line segments. Additionally, it presents a mathematical framework for modeling the proposed antenna and deriving an expression for its input impedance, thereby investigating the effects of various parameters on its bandwidth. The design of the proposed antenna utilizes an asymmetric coplanar waveguide (ACPW) due to its ease of implementation without the need for vias. Furthermore, the implementation of ACPW results in parasitic coplanar capacitances, which are used to tune the resonance modes of the proposed antenna, thereby extending its bandwidth. Curved corners are incorporated into the proposed antenna, and characteristic mode analysis (CMA) is used to investigate the effect of these curved corners on the significant modes and radiation pattern. The proposed antenna has electrical dimensions of $ 0.3\lambda _{0} \times \ 0.25\lambda _{0} \times \ 0.007\lambda _{0} $ 0.3λ0×0.25λ0×0.007λ0 at a frequency of 2.29 GHz. The antenna prototype has been fabricated and measured. The measured −10 dB fractional bandwidths are 48.1% (from 2.29 to 3.74 GHz), 30.5% (from 5.19 to 7.06 GHz), 7.1% (from 8.33 to 8.94 GHz), and 13.9% (from 9.74 to 11.19 GHz). Moreover, the measured maximum realized gain is 7.05 dBi. These features make the proposed antenna an attractive candidate for various wireless communication systems.