In this paper, a compact dual-band Dolly-shaped antenna (DBDSA), resonating at 23.52 GHz and 28.39 GHz, is proposed for automotive radar, 5G, and Industrial, Scientific, and Medical (ISM) applications. The antenna is designed on a 7 Â 7 Â 1.28 mm 3 which is 0.541λ 0 Â0.541λ 0 Â0.099λ 0 in electric size, where λ 0 represents the free space wavelength at 23.16 GHz. Rogers RO3010 substrate with a dielectric constant of 10.2 and a loss tangent is about 0.0022 has been used. Two F-shaped parasitic elements and a rectangular slot have been used to achieve the desired electromagnetic antenna performances. After modeling and optimizing the proposed antenna configuration through High-Frequency Structure Simulator (HFSS) software, its prototype was manufactured and measured to validate the simulated results. The DBDSA achieves an overall radiation efficiency of 80% within the two operating frequency bands. The radar band exhibits a stable gain of 5.51 dBi, while the 5G band has a gain of 4.55 dBi. Furthermore, the experimental results show that the |S 11 | -10 dB bandwidths are 1.16 GHz (23.16 GHz-24.32 GHz) in the lower band and 634 MHz (28.078 GHz-28.712 GHz), respectively. A good agreement is found between the simulated and measured results.

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We have presented an open-terminated transmission-line technique, based on the use of two substantially identical circular coaxial structures with different lengths, to extract the material relative permittivity ε r . All data acquisitions obtained from experimental measurements have been done at the entry of the connector-input source interface. The technique is well-utilized despite the test cell discontinuity, and it met the goal of extracting the relative intrinsic parameters with good accuracy. The technique improvement found its advantage in the scan of a large frequency range by introducing a new concept based upon the sum of the lengths of identical fixtures and the backward wave propagation. High order-modes propagation that restricts the frequency range in the transmission configuration is not a limit in this new technique. Otherwise, the measurement methodology, grounded in the principle of the automatic correction coefficient determination, is done to achieve the aim. Easily filling up the test cell with the sample to characterize, we validated the new broadband technique in [1.5 -15] GHz by using insulators like Aquarium sand, wheat semolina, and raffia (vinifera and laurentiis varieties). From the use of the same fixture, result comparisons have been done with those from the two-line technique.

A novel heart-shaped monopole antenna used in wireless portable communication devices is proposed and discussed in this paper. The antenna has a radiant patch surface area of 28.504 mm 2 , the physical size of 15 Â 12.5 Â 1 mm 3 , and electrical dimensions of 0.095λ 0 Â 0.079λ 0 Â 0.006λ 0 , where λ 0 denotes the wavelength of the free space at 1.89 GHz. Its prototype is printed on FR4 HTG-175, having a permittivity of 4.2 and a loss tangent of 0.019 at 1 GHz. The partial ground plane and two metallic vias connecting two open-ended branches of the slitted radiating patch to a parasitic conductor element results in about 98% miniaturization of the active patch area, as compared to the conventional antenna. The proposed antenna exhibits nearly an omnidirectional pattern in the elevation plane with a maximum radiation efficiency of 82.78% at 3.99 GHz, while a peak gain of 4.7 dBi is obtained at 6.5 GHz. The measured-6 dB impedance bandwidths demonstrate that the proposed quadband antenna operates in all the frequency bands of mobile telecommunication standards (2G/3G/4G/5G) and other applications, including WLAN, WiMAX, ISM, meteorological services, IEEE 802.11y, and C-band satellite communications. This antenna is easy to manufacture and can be used in most portable devices as a compact internal antenna. After simulating the modeled antenna using HFSS, a prototype was experimentally tested, and the measured results were compared with the data obtained by simulation. The parameters analyzed are return loss, bandwidth, and gain on all frequency bands. The fabricated prototype guarantees a minimum-10 dB bandwidth of 110 MHz and a maximum return loss of-12.2 dB, despite its low radiation efficiency of 21.43 % in the lower band dedicated to GSM applications. Furthermore, the proposed antenna operates as a narrowband and wideband.

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.