Mithilesh Kumar

In this project, a metamaterial-inspired multiband antenna with a size of 32 × 22 × 1.6 mm³ is designed on FR4 dielectric material that operates at eight wireless standards with gain enhancement application. The antenna has electrical dimension of 0.2581 λ × 0.1775 λ × 0.0129 λ (32 × 22 × 1.6 mm³), at a lower resonant frequency of 2.42 GHz. The proposed design has slots with Quasi CSRR (complementary split ring resonator) and SRR (split ring resonator) cell, respectively. Antenna achieves octa-band resonant modes for IoT and wireless applications S-band WLAN, bottom C-band WAIC, WLAN, bottom X-band, superior X-band, bottom Ku-band, superior Ku-band and bottom K band with optimized radiation properties. By the implementation of the proposed frequency selective surface (FSS) with design, antenna gain is improved for the resonant bands.

In this paper, a metamaterial-loaded hybrid fractal multiband antenna, using Moore and Koch curves regarding wireless standards, is presented. The antenna has an electrical dimension of 0.344 λ × 0.257 λ × 0.0187 λ (29.5 × 22 × 1.6 mm³) at 3.5 GHz and is fabricated on FR-4 epoxy substrate. The structure resonates at multiple frequencies, i.e. 3.5, 4.41, 5.8, 8.26, 10.48, 13.35 and 14.42 GHz with appropriate impedance matching (S₁₁ ≤ −10 dB) and achieves the peak gains 1.98, 2.38, 2.62, 3.91, 2.24, 3.28 and 4.11 dBi, respectively. The comparison of the simulated and measured results shows a good agreement. The frequency selective surface (FSS) is fabricated and tested. FSS is implemented with the antenna structure to enhance the antenna gain at achieved operating bands.

This paper propose a multiband antenna with implementation of metamaterial split ring resonator (SRR), quasi complementary split ring resonator (CSRR) and slots to achieve octa-band characteristics for wireless standards. Multiband features is accomplished by implementation of slot approach within radiating section part and loading the SRR, CSRR cell. Proposed design indicates the frequency band reconfigurability nature by using the switching PIN diode putting at the slotted section of ground plane. During OFF state of switching element structure resonating in eight wireless communication bands covering various high speed multiple applications of Internet of Things (IoT) regarding wireless standards S-band WLAN (WiFi, Bluetooth, Z-wave, wireless HART, WBAN), Lower C-band (WAIC, satellite communication transmission application), C-band WLAN, X-band (ITU region 2), Ku-band (Direct broadcast satellite system, Terrestrial microwave communication system service) and K band (Radar communication application) with S 11 ≤ -10 dB. The radiation characteristics (gain/efficiency/patterns/impedance matching) are shown in stable and improved form at achieved wireless modes.

This work presents a planar ultra-wideband (UWB) monopole antenna with controllable dual-band notches. In the proposed design, the lower and upper notch characteristics are realized by placing an inverted U-shaped slot on the radiating surface and another inverted U-shaped strip near to microstrip feed line, respectively. The controllable dual-notch frequencies are attained by placing varactor diodes at an appropriate position on the inverted U-shaped slot and inverted U-shaped strip, respectively. Simulation results show that the proposed antenna design has tunable band-notch characteristics from 5.58 GHz to 5.91 GHz and 7.02 GHz to 7.45 GHz, by decreasing the capacitance value from 2.67 pF to 0.63 pF. The fabricated prototype of the optimized design is characterized in three cases. A fairly good agreement is observed between the simulated and experimental results in all three cases. To the best of the authors’ knowledge, the dual tunable band rejects UWB is proposed for the first time in this paper.

In the present paper authors propose the design and analysis of a hepta band metamaterial inspired octagonal shape antenna using hybrid fractals for wireless applications. Multiband characteristics in the designed antenna is accomplished by introducing of slotted octagonal shape radiating part with hybrid fractal form of Moore curve and Koch curve and two SRR cells. The frequency band reconfigurability is obtained with aid of PIN diodes placed inside the strips connected between Moore curve (fused with centered Koch curve) and feedline. During ON mode of PIN diode antenna operates at seven microwave frequency S-band WiMAX (3.4 similar to 3.69 GHz-IEEE 802.16e)/Lower C-band terrestrial fixed and mobile broadband application (4.25 similar to 4.76 GHz)/C-band WLAN (5.15 similar to 5.35/5.75 similar to 5.825 GHz-IEEE 802.11a] (5.4 similar to 5.9 GHz)/Lower X-band Earth exploration-satellite service ITU region 2 (7.9 similar to 8.4 GHz)/Upper X-band Amateur satellite operating band (10.45 similar to 10.50 GHz)/Lower Ku-band Radar communication application (13.25 similar to 13.75 GHz)/Middle Ku-band Geostationary satellite service (14.2 similar to 14.5 GHz) covering various wireless applications. Proposed design exhibit hexa/hepta band features during OFF/ON mode of PIN diode. An acceptable gain, stable radiation characteristics, and good impedance matching are observed at all the resonant frequencies of the proposed structure.

This paper presents a double-printed circular slot inscribed, hexagonal shape miniaturized dipole antenna represents the ultra-wideband (UWB) characteristics with the implementation of linearly tapered feedline. The miniaturized UWB dipole antenna is designed for wireless applications wireless local area network (WLAN) and WiMAX by introducing a proposed metamaterial unit cell. Further, in comparison with the conventional UWB dipole antenna, miniaturization is achieved up to 35.89% and 16.67% with respective active patch area and antenna volume, respectively. The electrical dimension of the proposed antenna is 0.299 λ × 0.4385 λ × 0.0159 λ, of course, at lower frequency of 2.99 GHz. The use of metamaterial rectangular split-ring resonator and slotted ground structure witnessed the band achievements for wireless standards WLAN and WiMAX. The proposed structure is fabricated on FR4 substrate and tested. Impedance bandwidth of proposed antenna is obtained about 7.26% (2.39–2.57 GHz), 25.23% (2.91–3.75 GHz), and 16.92% (4.87–5.77 GHz) under simulation and 11.49% (2.38–2.67 GHz), 24.48% (2.94–3.76 GHz), and 15.99% (4.95–5.81 GHz) in measurement for WLAN (2.4–2.5, 5.150–5.250, and 5.725–5.825 GHz) and WiMAX (3.3–3.8 GHz) bands, respectively. Tunability between the wireless standards is demonstrated with the help of PIN diodes. The proposed design achieved high average gain of 3.31 and 2.06 dBi for simulation and measurement, respectively. The peak average radiation efficiency of 82.9% is observed during measurement mode. Experimental results are in good agreement with those obtained in the simulation of the proposed antenna.