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The proposed antenna was fabricated on low-cost, durable, 1.6-mm-thick reinforced fiberglass polymer resin substrate material. The relative permittivity of the substrate material is 4.6 with a loss tangent of 0.023. The substrate material consists of an epoxy matrix reinforced by woven glass. This composition of epoxy resin and fiberglass varies in thickness and is dependent upon direction. An attractive property of such polymer resin composites is that they can be shaped and reshaped repeatedly without losing their material properties.13

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 2

Due to the low manufacturing cost, ease of fabrication, design flexibility, and ready market availability of the proposed material, it has become a popular substrate for patch antenna design. The material is comprised of 60% fiberglass and 40% epoxy resin. Figure 2 features a photograph of the proposed antenna.

The performance of the antenna design was analyzed and optimized with the aid of FEM software and Ansoft’s HSFF EM simulator; it was plotted with the help of the OriginPro 8.5 software from OriginLab. The antenna prototype’s performance was measured in a standard far-field anechoic measurement chamber.

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 3

Figure 3 shows the simulated and measured VSWR of the proposed antenna. The impedance bandwidth (for a VSWR of less than 2.0:1) is 3.25 GHz, extending from 9.75 to 13.00 GHz. This shows that the lower resonance shifted from 10.5 to 10.3 GHz and the upper resonance shifted from 12.3 to 12.5 GHz. Figure 4 presents the gain achieved for the proposed antenna, from 0.6 to 6.03 dBi. Figure 5 highlights the antenna’s radiation efficiency, reaching 96% and 84.2%, respectively, at the lower and upper resonant frequencies.

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 4

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 5

Figure 6 provides a plot of the antenna’s input impedance, with the real part of impedance optimized to be as close as possible to 50 Ω. Figure 7 shows the current distribution along the antenna’s radiating patch, revealing that the intensity of the current distribution is higher at the upper resonant frequency than at the lower resonant frequency.

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 6

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 7

Figure 8 offers a Smith chart of the proposed antenna, validating the design’s input impedance and VSWR. The VSWR of the proposed antenna (less than 2.0:1) is within the circle. Figure 9 offers the E- and H-plane radiation patterns for the proposed antenna, with the almost steady radiation patterns at both 10.3- and 12.3-GHz resonant frequencies marking the antenna design as suitable for X- and Ku-band satellite-communications (satcom) applications.   

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 8

Low-Cost Substrate Supports Multiband Patch Antenna, Fig. 9

As the results for this low-profile antenna reveal, it is capable of a 3.25-GHz impedance bandwidth with VSWR of less than 2.0:1 from 9.75 to 13 GHz using a low-cost, durable, reinforced fiber-glass polymer resin material substrate. With peak gain of 8.5 dBi, the compact slotted patch antenna measures just 15 × 12 mm, and boasts excellent performance for a variety of applications.

M. Habib Ullah, Ph.D., Research Fellow

M.T. Islam, Researcher

J.S. Mandeep, Ph.D., Professor

N. Misran, Researcher

Department of Electrical, Electronics, and System Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Darul Ehsan, Malaysia

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