A tri‐band and miniaturized planar antenna based on countersink and defected ground structure techniques

In this article, a compact planar heart‐shaped antenna based on countersink and partial ground plane techniques is proposed to operate as a multiband device for modern wireless systems. With a surface area of 28.5 mm2, the countersink technique (CT) has been developed to achieve high electromagnetic antenna performance. The CT consists of a particular multilayer configuration that uses two distinct materials where one of them with a radiating element on its top is placed inside another. In this article, a 508‐μm thick Rogers RO4350B with a radiating patch designed on its top is thermally embedded into a 1.524 mm thick FR4 HTG‐175. The slits are used to get multiband behavior, and their combination with the defected ground structure results in about 79.58% reduction in resonant frequency compared to the conventional antenna. A mathematical model is developed to predict the resonant frequency of the proposed antenna configuration. After modeling the heart‐shaped antenna with an electromagnetic simulator, its prototype was manufactured and validated through experimental measurements. The CT considerably improved the antenna's performance compared to the use of a single layer technology for the same antenna configuration. The return loss read from −10 dB shows that the proposed antenna covers multiple modern wireless applications, including LTE bands, 5G, WLAN, WiMAX, and Unlicensed National Information Infrastructure (UNII) radio bands. Furthermore, the antenna operates as narrowband and wideband simultaneously on its lower/middle and upper operating frequency bands. A close agreement is found between simulated and measured results across all the frequency bands.