A Conformal CPW Folded Slot Antenna Array Printed on a Kapton Substrate Masud A. Aziz Sayan Roy* Layne A. Berge Irfanullah Sanjay Nariyal Benjamin D. Braaten Department of Electrical and Computer Engineering North Dakota State University Fargo, ND, USA

1) Introduction and Background 2) Conformal CPW Folded Slot Array 3) Measurement and Simulation Results 4) Proposed Design Guidelines 5) Conclusion Topics

Introduction and Background Schematic of the CPW (Co Planar Waveguide) –fed single folded slot antenna [1]: [1] D. E. Anagnostou and A. A. Gheethan, “A coplanar reconfigurable folded slot antenna without bias network for WLAN applications,”, IEEE Antennas And Wireless Propagation Letters, vol. 8, pp , Sep

Conformal CPW Folded Slot Array b = 5.00 mm, s = mm, w s = mm, L s = mm, r = mm, d = 2.00 mm, g = 0.63 mm, m = 1.79 mm, n = 0.71 mm, L f = 2.77 mm, P = 43.5 mm and Q = mm. Substrate Thickness : 0.05 mm Dielectric Permittivity: 2.91

Measurement and Simulation Results Printed two-element CPW folded slot antenna array on 2 mil Kapton substrate

Measurement and Simulation Results Prototype antenna diagram with a bend angle of ϕ b on a conformal surface (wedge)

Measurement and Simulation Results  The resonant frequency was measured to be 3.29 GHz with a 10dB bandwidth of 250 MHz for ϕ b =0°.  A good impedance match can be observed for each bend angle.  The impedance match of the antenna is essentially independent of ϕ b below 45 °.

The measured and simulated normalized field patterns on a conformal surface with ϕ b = 0° in x-z planein y-z plane

Measurement and Simulation Results Prototype antenna diagram with a bend angle of ϕ b on a conformal surface (wedge)

Comparison of the measured normalized field pattern in the x-z plane on a conformal surface with ϕ b = 0°

Comparison of the measured normalized field pattern in the x-z plane on a conformal surface with ϕ b = 30°

Comparison of the measured normalized field pattern in the x-z plane on a conformal surface with ϕ b = 45°

Measurement and Simulation Results

Proposed Design Guidelines b = 5.00 mm, s = mm, w s = mm, L s = mm, r = mm, d = 2.00 mm, g = 0.63 mm, m = 1.79 mm, n = 0.71 mm, L f = 2.77 mm, P = 43.5 mm and Q = mm. Changed Parameters: w s, L s, r, one at a time Changes in Geometry

Proposed Design Guidelines Effect of changes in w s (slot height) Observation: S11 can be improvised by increasing the dimension of the radiating slot of the antenna. Advantage: A better S11 can be obtained without changing the overall dimension of the antenna

Proposed Design Guidelines Effect of changes in L s (slot width) Observation: A second resonance point at 2.3 GHz has been found without any changes of the default characteristics of the antenna Advantage: Dual-band characteristics can be achieved without changing the overall dimension of the antenna

Proposed Design Guidelines Effect of changes in r (size of the dipole) Observation: The resonance frequency can be changed by decreasing the size of the dipole exciting the radiating slot of the antenna Advantage: The overall radiating frequency can be decreased without changing the overall dimension of the antenna

Conclusion Introduction and Background on the CPW-fed slot antenna has been discussed. Conformal CPW-fed slot antenna array has been introduced. Measurement and Simulation Results are compared for different bend angles of the surface of the antenna. New design guidelines have been proposed for the improvisation of the antenna characteristics.

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