Using Ansys HFSS and Circuit Design for UWB Antenna Optimization
Written by Cristian Iordan
Continental AG Romania
Continental AG is a global leader in automotive technology and innovation. The RF Antenna Design team develops advanced wireless access and sensing solutions for modern mobility platforms. By leveraging Ansys tools such as HFSS and Circuit Design, the team accelerates antenna development while meeting stringent electrical and mechanical requirements.
Task Description
Continental’s Antenna team set out to design a UWB antenna system for the COSMA platform (Continental Smart Access) that meets strict performance and manufacturing constraints. The main objectives were to achieve low input reflection coefficient across multiple UWB channels (CH5 to CH9), maintain stable radiation efficiency above −2 dB, and ensure robustness to PCB manufacturing tolerances. Passive impedance matching was not viable at these high frequencies, so an integrated electromagnetic and circuit-level design approach was required.
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Solution
Ansys HFSS: Used to model and simulate the full electromagnetic behavior of dipole antennas in the 6.25–8.25 GHz range. It enabled precise evaluation of radiation patterns, efficiency, and input matching.
Ansys Circuit Design: Integrated with HFSS to tune the hybrid coupler and microstrip geometries for each dipole. The solution allowed quick parametric optimization of structure dimensions, yielding optimized matching in seconds.
This workflow enabled the team to evaluate and redesign four UWB antennas, improving return loss and gain while preserving omni-directional coverage.
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Benefits
- Input reflection coefficient improved to below −15 dB across key UWB channels, exceeding the initial −10 dB target.
- Radiation efficiency maintained above −2 dB, with stable omnidirectional performance across multiple antenna positions.
- Tolerance-resistant design that accounts for ±10% variations in PCB thickness, substrate permittivity, and copper trace geometry.
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