Miniaturized stacked ring Archimedean spiral antenna with a stable radiation pattern for electromagnetic signal monitoring

This manuscript reports the miniaturization of the Archimedean spiral antenna using a stacked ring over a reflector. The Stacked Ring Archimedean Spiral Antenna (SRASA) has been fabricated on a double-sided RO4725JXR dielectric material with a thickness of 0.780 mm. A copper ring is placed beneath the Archimedean spiral with dielectric support. After attaching this ring, the bandwidth of the ASA has increased by 1.37 GHz in the lower frequency range while maintaining a 3-dB axial ratio (AR). A 24% miniaturization has been achieved. It exhibits a wide impedance bandwidth of 4.36–12 Ghz (93.3%) while also achieving an extensive 4.73–12 Ghz (86.9%) AR ≤3 dB, with an AR bandwidth of 86.9%. Notably, this high performance is realized with a very shallow reflector distance of only 7 mm. The effects of copper ring parameters on the antenna’s performance, including the S11 parameter, gain, and axial ratio, have been examined. Finally, the antenna has been fabricated and compared with the simulated results. This SRASA configuration is valuable for radiation applications requiring higher bandwidth with circularly polarized radiation. The compact design is suited for wideband electromagnetic signal monitoring applications.