Design and simulation of a rectangular microstrip patch antenna with dual-band operation, developed in CST Studio Suite. Two optimized slots are etched into the patch to produce resonance at two distinct bands, targeting IoT and WLAN applications.
Academic project for ECE 3208 — Antenna Engineering Laboratory, Department of Electronics and Communication Engineering, Khulna University of Engineering & Technology (KUET).
Conventional microstrip patch antennas operate over a single narrow frequency band. Modern wireless systems — 5G, radar, satellite links, and WLAN — require coverage across multiple bands while remaining compact and cheap to fabricate. This design addresses the usual limitations of single-band patch antennas: low gain, narrow bandwidth, and poor efficiency.
- Design a dual-band microstrip patch antenna in CST Studio Suite
- Simulate and analyze return loss, bandwidth, gain, and VSWR
- Optimize patch dimensions and the feeding mechanism to widen bandwidth, reduce return loss, and improve gain
Figure 1: Rectangular microstrip patch with two etched slots for dual-band operation.
Parameters were defined in CST and swept to tune both resonant frequencies. The slot width, slot length, and inter-slot spacing are the primary variables controlling the upper band.
Figure 2: S-Parameter magnitude vs frequency.
Resonance is achieved at both target bands with return loss well below the −10 dB threshold:
| Band | Resonant frequency | Return loss (S11) | Bandwidth |
|---|---|---|---|
| Lower | 7 GHz | −19.64 dB | 215.5 MHz |
| Upper | 15 GHz | −19.11 dB | 355 MHz |
Figure 3: Voltage Standing Wave Ratio.
| Band | VSWR |
|---|---|
| 7 GHz | 1.244 |
| 15 GHz | 1.2435 |
Both values sit comfortably below the standard limit of 2, indicating good impedance matching and efficient power transfer with minimal reflection.
Figure 4.1: Far-field radiation pattern at 7 GHz.
Figure 4.2: Far-field radiation pattern at 15 GHz.
The antenna was designed and simulated in CST Microwave Studio. Dual-band behaviour was obtained by etching two slots into the radiating patch and tuning their dimensions through parametric sweeps. The resulting bandwidths of 215.5 MHz and 355 MHz satisfy the requirements of IoT and WLAN applications, and the low VSWR at both resonant frequencies confirms effective impedance matching across both bands.
The design successfully achieves dual-band operation at 7 GHz and 15 GHz with strong impedance matching and favourable transmission characteristics. It is compact, planar, and cost-effective, making it suitable for wireless communication applications such as WLAN and Bluetooth. Future work will focus on fabricating the antenna and validating its performance through measurement.
- CST Studio Suite — electromagnetic simulation and optimization
Group project carried out by three students of ECE, KUET. Simulation, parametric optimization, and result analysis were shared across the team.
Simulation results only; the antenna has not yet been fabricated or measured.