This research article describes a compact multiband antenna using λ/4 rectangular stub, loaded with metamaterial for the frequency bands 2.4, 3.5, and 5.8 GHz allocated to IEEE 802.11n (WLAN) and IEEE 802.16e (WiMAX) standards in wireless communication. Compactness, multiband, and impedance matching operations in the proposed design are accomplished by utilizing a rectangular microstrip patch, a novel metamaterial based split ring resonator (SRR), a λ/4 rectangular stub and a ground plane. The proposed SRR negative permeability retrieval mechanism is explained in detail. The electrical dimensions of the designed antenna are 0.206 λ0 × 0.174 λ0 (25 × 22 mm2) at lower resonating band (2.4 GHz) and fabricated on a widely available FR4 substrate having 4.4 as dielectric constant and 1.6 mm as thickness. The average gain of 2.58 dBi, good impedance matching, stable radiation characteristics with high co‐polarization value and return loss bandwidth of 13.7% (2.26–2.57 GHz), 10.09% (3.27–3.60 GHz) and 5.09% (5.69–5.98 GHz) are observed at the bands of operation when the antenna is fabricated and tested. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1000–1006, 2017

The progress of technology in consumer electronics demand an antenna having a compact size, high gain and bandwidth, and multiple antennas at transmitter and receiver to enhance the channel capacity. Over the last decade, numerous techniques are proposed to improve the performance of the antenna. One such technique is the use of metamaterials (MTMs) in antenna design. MTMs are artificial structures to provide unique electromagnetic properties that are not available in natural materials. The unique properties of these materials allow the design of high-performance antennas, filters, and microwave devices which cannot be obtained using traditional antennas. Loading antenna with the one, two, and three-dimensional MTM structures comprised of a periodic subwavelength unit cell exhibits RLC resonant structures and allows to manipulate electromagnetic waves in the antenna system. These structures offer low resonant frequency compared to the antenna resonant frequency resulting in antenna miniaturization and manipulation of electromagnetic waves helps in enhancing the gain and bandwidth, and achieving circular polarization (CP) of an antenna system. Also, metamaterial loading enhances isolation between the antenna elements in the multiple-input-multiple output (MIMO) system by suppressing the surface waves. In this paper, the electromagnetics of MTM with analytical expressions and its application in antenna design are discussed in detail. The MTM-based antennas are classified into MTM loading, MTM inspired antenna, metasurface loading, and composite right/left hand (CRLH) based antennas. The recent development in MTM inspired antenna and its application in antenna miniaturization, enhancing gain and bandwidth, achieving CP and mutual coupling suppression in MIMO antenna systems are discussed to make it useful for further research. INDEX TERMS Circular Polarization (CP), Metamaterial (MTM), gain, bandwidth, high impedance surface (HIS), mutual coupling, antenna miniaturization, composite right/left hand (CRLH).

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Fractal geometry has been proven to be useful in several disciplines. In the field of antenna engineering, fractal geometry is useful to design small and multiband antenna and arrays, and high-directive elements. A historic overview of the most significant fractal mathematic pioneers is presented, at the same time showing how the fractal patterns inspired engineers to design antennas.