Design of dual‐band annular slot antenna with strip‐loaded approach

This article investigation develops and experimentally explores the dual‐band design for a compact coplanar waveguide (CPW)‐fed annular slot antenna loaded with conducting strips.In the proposed strip‐loaded design, the arc‐like metal strips excite the first resonant mode at the operating frequency, which is lower than that of the annular slot antenna, to achieve miniaturization. The prototype is implemented on a 0.8 mm FR‐4 substrate with εr = 4.4; the outer and inner radii of the compact annular slot are 9.0 mm and 6.5 mm, respectively. The return loss of the proposed design reveals two operating bands with a VSWR of 2.5: 1 over bandwidths of 3.5% and 9.8%, respectively. Two resonant bands exhibit the broadside radiation patterns with the peak antenna gains of 1.3 dBi and 4.9 dBi, respectively.