Dual-band Elliptical Patch Antenna for GPS and Iridium Applications
The design and implementation of a circularly polarized dual-band elliptical patch antenna is a challenging task due to the requirement of special feeding techniques and the other following reasons:
- Compact, light-weight, low profile, and low maintenance.
- Resonances and circular polarization in two close frequency bands (GPS and Iridium bands).
AI-driven Design with SADEA-III
The optimization problem is stated as follows:
- Maximum reflection coefficient (S11) < -10 dB (1.563 GHz to 1.587 GHz)
- Maximum reflection coefficient (S11) < -10 dB (1.616 GHz to 1.626 GHz)
- Maximum axial ratio (AR) < 10 dB (1.563 GHz to 1.587 GHz)
- Maximum axial ratio (AR) < 5 dB (1.616 GHz to 1.626 GHz)
Synthesis and Measurement Results
The design obtained by SADEA-III  is verified through a physical implementation.
For this case:
- The synthesized antenna by SADEA-III obtains a maximum return loss of -12.4 dB and -13.96 dB, and an axial ratio of 3.4 dB and 4.5 dB, over the GPS and Iridium bands, respectively in half a day.
- The measured results are in close agreement with the simulation results.
- The size of the fabricated antenna is 94.3 mm × 94.3 mm × 2.6 mm.
- This shows over 2.6 times area reduction compared to the previous similar design .
Comparison with Other Methods
The performances of SADEA-I  and SADEA-III  are compared with the following methods:
- 2019 Computer Simulation Technology-Microwave Studio: Particle Swarm Optimization (2019 CST-MWS: PSO)
- 2019 Computer Simulation Technology-Microwave Studio: Trust Region Framework (2019 CST-MWS: TRF)
- A sigma value of unity is used to direct the search towards global optimum and all initial designs for each run are randomly generated using Latin hypercube sampling.
Note that results from designs with geometric constraint violation are not included and are designated as not applicable (N/A) because in practice, such designs cannot be used due to geometric incongruities.
- B. Liu, M. O. Akinsolu, N. Ali and R. Abd-Alhameed, “Efficient Global Optimisation of Microwave Antennas Based on a Parallel Surrogate Model-Assisted Evolutionary Algorithm“, IET Microwaves, Antennas and Propagation, vol. 13, no. 2, pp. 149 – 155, 2019.
- B. Liu, H. Aliakbarian, Z. Ma, G. A. Vandenbosch, G. Gielen and P. Excell, “An Efficient Method for Antenna Design Optimization based on Evolutionary Computation and Machine Learning Techniques.“, IEEE Transactions on Antennas and Propagation, vol. 62, no. 1, pp. 7 – 18, 2014.
- K. K. Mistry, P. I. Lazaridis, Z. D. Zaharis, B. Liu, et al., “A Design of Elliptical Edge-Fed Circularly Polarized Patch Antenna for GPS and Iridium Applications.” URSI Atlantic Radio Science Meeting (AT-RASC), 2018.