In this work, an integrated antenna system with Defected Ground Structure (DGS) is presented for Fourth Generation (4G) and millimeter (mm)-wave Fifth Generation (5G) wireless applications and handheld devices. The proposed design with overall dimensions of 110 mm × 75 mm is modeled on 0.508 mm thick Rogers RT/Duroid 5880 substrate. Radiating structure consists of antenna arrays excited by the T-shape 1 × 2 power divider/combiner. Dual bands for 4G centered at 3.8 GHz and 5.5 GHz are attained, whereas the 10-dB impedance bandwidth of 24.4 -29.3 GHz is achieved for the 5G antenna array. In addition, a peak gain of 5.41 dBi is demonstrated across the operating bandwidth of the 4G antenna array. Similarly, for the 5G mm-wave configuration the attained peak gain is 10.29 dBi. Moreover, significant isolation is obtained between the two antenna modules ensuring efficient dual-frequency band operation using a single integrated solution. To endorse the concept, antenna prototype is fabricated and far-field measurements are procured. Simulated and measured results exhibit coherence. Also the proposed design is investigated for the beam steering capability of the mm-wave 5G antenna array using CST MWS . The demonstrated structure offers various advantages including compactness, wide bandwidth, high gain, and planar configuration. Hence, the attained radiation characteristics prove the suitability of the proposed design for the current and future wireless handheld devices.INDEX TERMS Antenna array, integrated solution, 4G, mm-wave 5G, handheld devices.

Owing to the rapid growth in wireless data traffic, millimeter-wave (mm-wave) communications have shown tremendous promise and are considered an attractive technique in fifth-generation (5G) wireless communication systems. However, to design robust communication systems, it is important to understand the channel dynamics with respect to space and time at these frequencies. Millimeter-wave signals are highly susceptible to blocking, and they have communication limitations owing to their poor signal attenuation compared with microwave signals. Therefore, by employing highly directional antennas, co-channel interference to or from other systems can be alleviated using line-of-sight (LOS) propagation. Because of the ability to shape, switch, or scan the propagating beam, phased arrays play an important role in advanced wireless communication systems. Beam-switching, beam-scanning, and multibeam arrays can be realized at mm-wave frequencies using analog or digital system architectures. This review article presents state-of-the-art phased arrays for mm-wave mobile terminals (MSs) and base stations (BSs), with an emphasis on beamforming arrays. We also discuss challenges and strategies used to address unfavorable path loss and blockage issues related to mm-wave applications, which sets future directions.

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This research article proposes a compact frequency and pattern reconfigurable flexible antenna for heterogeneous applications. A triangular monopole antenna with a semicircular stub is made frequency and pattern tunable by connecting and disconnecting two inverted L-shaped stubs utilizing diodes. When either of the stubs is connected to the radiator, a relative phase difference happens at both ends of the radiator that changes the direction of the electromagnetic radiations, consequently pattern reconfigurability can be obtain. Besides that, because of the reactive load introduced by the stubs, the antenna’s effective length has changed and, as a result, the frequency reconfigurability can be attained. The antenna features a compact size of 40 × 50 × 0.254 mm3 corresponding to 0.22λo × 0.27λo × 0.001λo, where λo is free-space wavelength at 1.65 GHz, while its operational bandwidth is from 1.65 GHz to 2.51 GHz, with an average gain and radiation efficiency of better than 2.2 dBi and 80%, exhibiting a pattern reconfigurability of 180° in the E-plane. The frequency of the proposed antenna can be switched from 2.1 GHz to 1.8 GHz by switching the state of both diodes in OFF and ON-state, respectively. The fabricated prototype of the antenna is tested to verify its performance parameters. In addition, to validate the proposed design, it has been compared with prior arts in terms of the overall size, reconfigurability type, flexibility, radio frequency (RF) switch type used for reconfigurability, and frequency bandwidth. The proposed antenna provides smaller size with a large bandwidth coverage alongside with discrete RF switch type with the advantages of flexibility and both frequency and pattern reconfigurability. As a result, the proposed compact flexible and pattern reconfigurable antenna is a promising candidate for heterogeneous applications, including the global system for mobile (GSM) band (1800 and 1900 MHz) and industrial, scientific and medical (ISM) band (2.4 GHz) along with well-known cellular communication bands of 3G, 4G, and long term evolution (LTE) bands ranging from 1700–2300 MHz around the globe.

The purpose of this study was to produce a kirigami inspired split ring resonator (SRR) strain sensor. Since the SRR resonance frequency depends strongly on its split gap, one kirigami cut was designed to align with the SRR split gap, allowing SRR resonance frequency to be varied by applying tensile stress. The relationship between frequency and induced strain helps to explain the strain sensing mechanism. Two sheets of paper were used as the dielectric for compatibility with the kirigami technique, and a conductive pattern was inkjet printed on the top paper using silver nanoparticle ink, whereas the ground plane on the bottom paper was inkjet printed using stretchable ink. The two papers were bonded using epoxy strain sensor and S parameters for the fabricated sensor were measured at different strain levels. Resonance frequency increased from 4 to 4.64 GHz for 17.24% applied strain, with measured strain sensitivity=4.2×10 7 Hz/% and minimum detectable strain level ≈0.84%. Measurement results were compared with simulation results. The proposed strain sensor is relatively easy to manufacture, low cost, and disposable because it was inkjet printed on paper.

In this paper, we demonstrate a V-band planar micromachined helical antenna (PHA) with end-fire radiation on the glass substrate. The planar rectangular helical configuration is realized using the novel through-glass silicon via (TGSV) technology. The proposed micromachined antenna is designed and fabricated on a borosilicate glass substrate of thickness 350 µm, which has a very low-dielectric loss compared to silicon at millimeter-wave bands. The proposed PHA is fed by a microstrip line, and the planar helical configuration with 3.25 turns with a truncated ground plane is designed for achieving wideband end-fire radiation with seven tungsten-coated silicon vias and six connected gold arm patterns, which are fabricated using the TGSV technology. The electrical length of the proposed antenna is (3 λ o ×1.4 λ o). The designed antenna operates at the center frequency of 58 GHz. A prototype of the proposed antenna is fabricated by micromachining technology and tested. The simulated and measured results show that the proposed antenna has a wide operational bandwidth of 50.3 to 65 GHz for |S 11 | < −10 dB with a fractional bandwidth (FBW) of 25.5%. The measured peak gain is 6.3 dBi, and measured efficiency is 62% at the center frequency of 58 GHz. All measurements are in close agreement with simulated results. The proposed planar helical antenna with end-fire radiation is useful for applications in traveling-wave-tubes operating in millimeter-wave and higher frequencies, millimeter-wave on-board wireless communication, radar imaging, and tracking applications. INDEX TERMS Borosilicate-glass, end-fire, planar helical antenna, through glass silicon via (TGSV), travelling-wave-tubes (TWTs).

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In this article, a novel super‐wideband planar microstrip‐fed monopole antenna is investigated and designed. The antenna consists of a well‐optimized hut‐shaped radiating patch having a diamond‐shaped slot window at its center. To achieve nearly omnidirectional pattern, a partial ground plane consisting of an optimized slit exactly on the opposite of the feed line is used. Measurement results show that the impedance bandwidth for |S11|dB ≤ 10 dB is enhanced largely to 184.5% with a ratio bandwidth more than 24.8:1 (0.9 − 22.35 GHz). This, together with its nearly constant measured gain of 3.35 dBi ±1 dB over this entire band makes it a potential candidate for both ultra‐wideband and super‐wideband applications. Moreover, the proposed antenna has a compact size of 40 × 25 mm2 on 1.6 mm thick FR4 substrate with dielectric constant of 4.4. Details of the proposed antenna are described, and both theoretical and experimental results are presented. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2645–2649, 2015