A THREE-STAGE SLOTTED HEXAGRAM MICROSTRIP PATCH ANTENNA DESIGN AND S-PARAMETER ANALYSIS FOR K-BAND AND 5G N258 APPLICATIONS

This paper presents a simulation-based study of a three-stage slotted hexagram microstrip patch antenna intended for 24 GHz K-band and millimeter-wave applications. A six-pointed-star (hexagram) patch on a 40 mm × 40 mm FR4 substrate is fed by a 3 mm microstrip line and analyzed in Ansys HFSS with a lumped port over a 2–30 GHz sweep. The geometry evolves from a solid hexagram (Stage 1), to a hexagram with six triangular arm slots (Stage 2), to a hexagram with six triangular arm slots and a central circular slot (Stage 3). The reported S11 minima are −11.8980 dB at 25.10 GHz, −12.8660 dB at 24.96 GHz, and −16.7466 dB at 24.60 GHz for Stages 1–3, respectively, i.e., a 500 MHz downward shift of the marked resonance and an S11 improvement of about 4.85 dB. The Stage 3 resonance lies within the 5G NR n258 range (24.25–27.50 GHz). S₁₁, VSWR, and a simulated gain pattern at the Stage 3 resonance are reported; impedance bandwidth, quantified gain, efficiency, and measurements remain future work.