Case Six

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Hexagonal Meta-surface Based Wide Band Antenna for Wireless Communications

Problem Description

Design Challenges

The design and implementation of the hexagonal meta-surface based wide band antenna is very challenging mainly due to the following reasons:

  • Large fractional bandwidth and gain requirements covering two operating frequency bands, 2 GHz to 3.5 GHz and 4.2 GHz to 8.2 GHz
  • Stable radiation pattern and realized gain within the two desired frequency bands, 2 GHz to 3.5 GHz and 4.2 GHz to 8.2 GHz.
  • Compact, light-weight, low profile, and low maintenance with a simple feeding structure.

 

AI-driven Design with SADEA-III

Optimization Problem

For the given hexagonal meta-surface based wide band antenna antenna structure, the specifications set as the optimization goals are as follows:

  • Maximize the fractional bandwidth for a maximum return loss of -9 dB and minimum realized gain of  3.5 dBi in the band 2 GHz to 3.5 GHz
  • subject to: 
    • Maximum reflection coefficient (S11) < -10 dB (2.4 GHz to 2.5 GHz) 
    • Minimum realized gain (G) > 3.5 dBi (2.4 GHz to 2.5 GHz) 
  • Maximize the fractional bandwidth for a maximum return loss of -9 dB and minimum realized gain of  6 dBi in the band 4.2 GHz to 8.2 GHz
    subject to: 

     

    • Maximum reflection coefficient (S11) < -10 dB (4.2 GHz to 8.2 GHz) 
    • Minimum realized gain (G) > 3.5 dBi (4.2 GHz to 8.2 GHz) 

 

Layout of the Hexagonal Meta-surface Based Wide Band Antenna

(a) The Geometry of the Hexagonal Meta-surface Based Wide Band Antenna: Top and Side Views

(b) Top and Bottom Views. 

 

Ranges of the 21 Design Variables for the Design Exploration

 

Synthesis and Measurement Results

The design obtained by the SADEA-III is verified through a physical implementation.

 

For this case:

  • The synthesized antenna by the latest SADEA-III obtains the following results in 10 days.
    • Fractional bandwidth of (2.26 GHz to 2.79 GHz) over 2 GHz to 3.5 GHz with a maximum reflection coefficient of -9 dB and minimum realized gain of 3.9 dBi in the fractional bandwidth.
      • Maximum reflection coefficient (S11) = -10.0 dB (2.4 GHz to 2.5 GHz)
      • Minimum realized gain (G) = 3.9 dBi (2.4 GHz to 2.5 GHz)
    • Fractional bandwidth of (4.95 GHz to 7.8 GHz) over 4.2 GHz to 8.3 GHz with a maximum reflection coefficient of -9 dB and minimum realized gain of 6.2 dBi in the fractional bandwidth.
      • Maximum reflection coefficient (S11) = -10.2 dB (5.0 GHz to 6.0 GHz)
      • Minimum realized gain (G) = 6.2 dBi (5.0 GHz to 6.0 GHz)
  • The measurement results are in close agreement with the simulation results.