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In wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is maximizing the connectivity to cover different wireless services that operate different frequency range. Pattern reconfigurable antenna can improve security, avoid noise and save energy. Due to their compactness and better performance at different applications, reconfigurable antennas are very popular among the researchers. The purpose of this work, is to propose a novel design of S-shaped antenna with frequency and pattern diversity. The pattern and frequency reconfiguration are controlled via ON/OFF states of the PIN diode.

The geometrical structure of the proposed antenna dimension is 18 × 18 × 0.787 mm³ with εr = 2.2 dielectric constant. Three S-shaped patches are connected to a ring patch through PIN diodes. The approximate circumference of ring patch is 18.84 mm and length of patch is 5 mm, so approximate length of radiating patch is 14.42 mm and effective dielectric constant is 1.93. Conductor backed coplanar waveguide (CPW) is used for feeding. The proposed antenna is designed and simulated on CST microwave studio and fabricated using photolithography process. Measurements have been done in anechoic chamber.

Antenna shows the dual band operation at 2.1 and 3.4 GHz frequency. The first band remains constant at 2.1 GHz resonant frequency and 200–400 MHz impedance bandwidth. Second band is switched at seven different resonant frequencies as 3.14, 3.45, 3.46, 3.68, 3.69, 3.83 and 3.86 GHz with switching of the diodes. The −10 dB bandwidth is more than 1.4 GHz.

Pattern reconfigurability can be achieved using mechanical movement of antenna easily but it is not a reliable approach for planar antennas. Electronic switching method is used in proposed antenna. Antenna size is very small so fabrication is very crucial task. Measured results are deviated from simulation results due to fabrication error and effect of leads of diodes, connecting wires and battery.

The reconfiguration of the proposed antenna is controlled via ON/OFF states of the three PIN diodes. The lower band of 2.1 GHz is fixed, while second band is switched at five different resonant frequencies as 3.27, 3.41, 3.45, 3.55 and 3.88 GHz, with switching of the PIN diodes with all state of diodes and exhibit pattern reconfigurability at 2.1 GHz frequency. At second band center frequency is significantly changed with state of diodes and at 3.4 GHz pattern is also changed with state of diodes, hence antenna exhibits frequency and pattern reconfigurability.

A novel design of pattern and frequency reconfigurable antenna is proposed. Here, work is divided into two parts: first is frequency reconfiguration and second is radiation pattern reconfiguration. PIN diodes as switch are used to select the frequency band and reconfigure the radiation pattern. This proposed antenna design is novel dual band frequency and pattern reconfigurable antenna. It resonates at two distinct frequencies, i.e. 2.1 and 3.4 GHz, and has a pattern tilt from 0° to 355°. The conductor backed CPW feed technique is used for impedance matching.

Use of thin film microstrip patch antenna for leaf moisture studies.

In this paper, the studies on the effect of leaf used as in‐touch overlay on thin film microstrip patch antenna in the X band (8‐12 GHz) is reported. The patch was used as the transmitting antenna and a pyramidal horn antenna was the receiving antenna. Three leaves Furcarea Gigantea, Kalanchoe Pinnata and Cereus Prerogonus have been used as overlay. All these leaves have high chlorophyll content, but are different in their surface texture and rate of moisture loss.

Size of leaf, orientation with respect to direction of propagation and moisture content dependent changes in the patch antenna output are observed. When the size of the overlay is larger than the patch and the feedline is in contact with it, frequency changes are more, whereas when only patch is in contact with the leaf, amplitude changes are more. Thin film microstrip antenna can provide a means for sensing moisture content in leafy vegetation.

The study of moisture effects of leafy vegetation using the technique of in‐touch overlay on microstrip components can be used to generate data base about the plant conditions in various places.

This paper aims to propose a cylindrical conformal wideband antenna with increased directive behaviour using integrated parasitic triangular-shaped elements for WiMAX application.

The proposed antenna is a wideband directional cylindrical conformal antenna consisting of three fork-shaped dipole elements incorporated with parasitic triangular-shaped reflecting components increases the gain of reference conformal antenna. The novel parasitic elements with triangular shapes are designed on the radiating patch as well as the ground plane side. The parasitic triangular elements enable the antenna to enhance the gain along the end-fire direction.

The proposed antenna has a 20.2% impedance bandwidth ranging from 3.1 to 3.8 GHz. The half power beam-width (HPBW) of the reference antenna in the H-plane is 122.9° and falls to 99.1° after integrating with parasitic elements at 3.3 GHz, whereas it falls from 56.7° to 54.7° in the E-plane. However, at 3.5 GHz, the reference antenna’s HPBW is at 116.8°, which decreases to 92.4° in the H-plane, whereas it reduces from 57.9 to 53.4° in the E-plane. The proposed antenna has a lower HPBW than reference antennas and achieved a gain enhancement of 1.2 dBi, indicating that the pattern becomes more directed.

In the proposed work, the directive behaviour of cylindrical conformal antenna structure with a 30 mm radius of curvature is improved using parasitic reflective elements. The fabricated antennas’ experimental findings are an excellent contender for wireless point-to-point WiMAX applications because it features a wideband, directional properties, and strong gain over the whole operational frequency range of 3.1–3.8 GHz.

This study aims to investigate different configurations of plasma antenna arrays and multiple combinations based on whether the plasma dischargers are set ON or OFF, to assess the coupling, interference and overall performance of these plasma antenna arrays.

In this paper, the authors investigate the operation and performance of the combined use of sets of antennas and plasma antenna elements in plasma monopole antenna arrays.

The authors find that there can be significant modifications of the plasma antenna arrays’ gain and pattern in multiple ways, merely by switching different combinations of plasma columns ON and OFF.

High-density plasma antenna arrays have been examined in this paper and it has been shown that they are capable of reaching high antenna gain. Moreover, the overall antenna array’s gain and pattern can be considerably transformed in multiple ways by turning ON and OFF different combinations of plasma antenna elements. Finally, the electromagnetic coupling and interference coming from these plasma antennas can be greatly reduced.

This paper aims to present the design of a compact quad-band coplanar-fed monopole antenna for tablet computer applications.

The antenna has the smallest size of 26 × 14 mm and supports GSM, Wi-Fi, WIMAX and Bluetooth. The proposed antenna consists of a coplanar fed main radiator, c-shaped stubs and parasitic meandered stub. The inverted c-shaped stubs enhance the bandwidth of upper frequencies. The resonance at 2.4 GHz is individually controlled by the coupled meandered stub.

The percentage bandwidth in the four operating bands are 8.7/4.12/27.8/13.3%. Furthermore, the antenna is integrated with the mock-up ground plane and specific absorption rate (SAR) calculations are performed. The estimated SAR is less than 1.6 W/kg for a 1 g body tissue. The gain and efficiency of the antenna are 3.56/4.37/4.97/6 dBi and 82.4/85/97.1/89.3%, respectively. The measured impedance and radiation characteristics of the fabricated prototype are in good correlation with the simulated results.

In the proposed work, vias and lumped elements are not used for lower band excitation, and most of the wireless applications in the tablet computers have been covered. Further, the effect of antenna with different orientation has been tested for the estimation of SAR.

The fifth-generation technology 5G, the planned successor to 4G, is a new global standard for mobile networks that brings virtual to reality. 5G wireless technology enables the delivery of high speed, low latency, reliability, 100% coverage and availability to connect number of users as in massive IoT applications.

With expeditious development in wireless communication, the need for enhanced characteristic antenna design such as the size of the antenna, high data rate, demand in traffic, bandwidth, gain and efficiency increases. Various antenna designs are to be explored to meet the needs and achieve trade-offs between antenna size vs cost, high gain and efficiency vs less loss, high B.W and data rate with the selection of appropriate substrate materials and various gain & isolation enhancement techniques.

This paper thus gives scope for miniaturized MIMO antenna design for mobile applications at mm-wave frequency range.

This paper thus gives scope for miniaturized MIMO antenna design for mobile applications at mm-wave frequency range.

An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands of multi-input multi-output (MIMO) antenna. These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the impedance bandwidth (IBW) of the MIMO antenna, and its diligent adjustment of it leads to cover the frequency range of Bluetooth and Wireless Local Area Network systems.

A new MIMO antenna is introduced in this paper in conjunction with an enhanced Wilkinson power divider feeding platform.

These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the IBW of the MIMO antenna, and its diligent adjustment leads to covering the frequency range of Bluetooth and WLAN systems.

The proposed MIMO antenna benefits from good isolation between ports for both frequency bands. The proposed MIMO antenna is constructed on FR4 substrate with a volume of 90 × 134 × 1.6 mm3.

This paper aims to present a new triangular crinkle-shaped multiband antenna for multiband operation.

This paper refers to increasing the number of resonance frequency by appending triangular crinkle. Experimental frequency results of the presented antenna are 1.60/2.80/4.00/5.80/7.12/8.32/10.06 GHz.

The triangular shaped antenna is manufactured on a low-priced FR-4 substrate with small size and tested. The reported antenna with full size 14 × 14 mm² with a half elliptical ground sheet on the bottom plane of the substrate and a triangular crinkle strip patch in the front of the substrate. The reported antenna has dual polarized, by rectangular slits on the ground sheet can produce the CP radiation on ITU band. The radiation characteristics indicate the mentioned antenna plays good task for multiband structures. Simulation and measured consequences are in desirable agreement and refer to agreeable operation for the introduced antenna.

Also, an evaluation is done based on multiple attribute decision-making method for comparison the proposed monopole antenna with some previously presented multiband monopole antennas.

The purpose of this paper is to present a new dual-band printed monopole antenna with a partial ground with two notched bands based on electromagnetic band gap (EBG) structures. A new type of EBG antenna with radiation patterns and antenna gains over the operating bands has been developed.

The proposed antenna consists of a pair of EBG structures using a transmission line model. The proposed antenna is designed on an FR4 substrate with a thickness of 1 mm and permittivity (e_r) = 4.3.

The measured results show good dual-band operations with −10 dB impedance bandwidths of 9.1 and 36.2 per cent centered at 2.45 and 6.364 GHz, respectively, which covers the wireless local area network (WLAN) operating bands.

A new type of EBG antenna with radiation patterns and antenna gains over the operating bands has been developed.

The purpose of this study is to develop a method to reduce the computation time necessary for the automated optimal design of dual-band wearable antennas. In particular, the authors investigated if this can be achieved by the use of a hierarchical optimization paradigm combined with a simplified human body model. The geometry of the antenna under consideration is described via eight geometrical parameters which are automatically adjusted with the use of an evolutionary algorithm to improve the impedance matching of an antenna located in the proximity of a human body. Specifically, the antennas were designed to operate in the ISM band which covers two frequency ranges: 2.4-2.5 GHz and 5.7-5.9 GHz.

During the studies on the automated design of wearable antennas using evolutionary computing, the authors observed that not all design parameters exhibit equal influence on the objective function. Therefore, it was hypothesized that to reduce the computation effort, the design parameters can be activated sequentially based on their influence. Accordingly, the authors’ computer code has been modified to include this feature.

The authors’ novel hierarchical multi-parameter optimization method was able to converge to a better solution within a shorter time compared to an equivalent method not exploiting automatic activation of an increasing number of design parameters. Considering a significant computational cost involved in the calculation of the objective function, this exhibits a convincing advantage of their hierarchical approach, at least for the considered class of antennas.

The described method has been developed for the design of single- or dual-band wearable antennas. Its application to other classes of antennas and antenna environments may require some adjustments of the objective functions or parameter values of the evolutionary algorithm. It follows from the well-recognized fact that all optimization methods are to some extent application-specific.

Computation load involved in the automated design and optimization can be significantly reduced compared to the non-hierarchical approach with a heterogeneous human body model.

To the best of the authors’ knowledge, the described application of hierarchical paradigm to the optimization of wearable antennas is fully original, as well as is its combination with simplified body models.