Design and Analysis of Microstrip Patch Antennas Using Artificial Neural Network

The microstrip patch antenna can also be designed using an artificial neural network (ANN) modeling technique where size of the antenna is major limitation especially in mobile and wireless applications. In this chapter, analysis and synthesis problems for designing of microstrip patch antennas were discussed using the artificial neural network technique. An analysis problem refers to calculation of resonant frequency of microstrip patch antenna whereas a synthesis problem refers to calculation of dimensions of patch antenna. Both problems are reciprocal of each other. Results are implemented using graphical user interface (GUI) tools of MATLAB programming language. Back‐propagation training algorithm of artificial neural network is used to train the network for minimization of error and computation time. Therefore, the geometric dimensions of patch are obtained with high accuracy in less computation time as compared to simulation software

Multiband Antennas Design Techniques for 5G Networks: Present and Future Research Directions

With the development of wireless communication system has demanded compact wireless devices that allow more space to integrate the other electronics components. Advancement in technology creates challenges in implementing antenna for multiple RF band with a wide range of frequencies. With the advancement of optimization technique we can improve the antenna design as well as provide us the motivation of analyzing the existing studies in order to categorize and synthesize them in a meaningful manner. The objective of this paper contributes in two ways. First, it provides the research and development trends and novel approaches in design of multiband MIMO, smart reconfigurable and defected ground structure (DGS) antenna techniques for wireless system. Secondly, it highlights unique design issue reported in literature. The proposed paper aim is filling the gap in the literature and providing the researcher a useful reference

Design and Analysis of Dual Band Micro strip Patch Antenna

This thesis involves the design and analysis of Dual band Microstrip patch antenna which operates at lower and upper resonating frequency of 3.05 GHz and 7.24 GHz respectively. Basically transmission line modelling approach has been used to model the antenna. The proposed antenna has been fed with 50O microstrip feed line. In the first frequency band we have bandwidth of 310MHz (2.91-3.22 GHz) with gain and directivity 3.304dB and 4.393dBi respectively. The second frequency band has a bandwidth of 580MHz (6.69-8.27 GHz) with gain and directivity of 3.534dB and 5.516dBi. Radiation efficiency at the two bands of operations are 75.12% and 63.52% respectively. Design parameters for the proposed antenna have been calculated from the transmission line model equations considering the effects of introducing inset notch parallel to the radiating edge of the antenna. Ground plane dimensions have been optimized by analyzing the antenna characteristics through parametric study. The CST Microwave Studio software has been used to implement the desired design and various antenna parameters have been studied. Furthermore, an attempt has been taken to calculate the return loss vs frequency response through MATLAB coding. The proposed antenna covers a good portion of S-band and C-band. It can be embedded in mobile devices for the purposes of mobile WiMAX, Wi-Fi, Bluetooth and WLAN operations due to its very small size and weight. Also it can be used by weather radar, surface ship radar, and some communications satellites for various surveillance and communication purpose

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

Analysis, design and implementation of front-end reconfigurable antenna systems (FERAS)

The increase in demand on reconfigurable systems and especially for wireless communications applications has stressed the need for smart and agile RF devices that sense and respond to the RF changes in the environment. Many different applications require frequency agility with software control ability such as in a cognitive radio environment where antenna systems have to be designed to fulfill the extendable and reconfigurable multi-service and multi-band requirements. Such applications increase spectrum efficiency as well as the power utilization in modern wireless systems. The emphasis of this dissertation revolves around the following question: Is it possible to come up with new techniques to achieve reconfigurable antenna systems with better performance?\u27 Two main branches constitute the outline of this work. The first one is based on the design of reconfigurable antennas by incorporating photoconductive switching elements in order to change the antenna electrical properties. The second branch relies on the change in the physical structure of the antenna via a rotational motion. In this work a new photoconductive switch is designed with a new light delivery technique. This switch is incorporated into new optically pumped reconfigurable antenna systems (OPRAS). The implementation of these antenna systems in applications such as cognitive radio is demonstrated and discussed. A new radio frequency (RF) technique for measuring the semiconductor carrier lifetime using optically reconfigurable transmission lines is proposed. A switching time investigation for the OPRAS is also accomplished to better cater for the cognitive radio requirements. Moreover, different reconfiguration mechanisms are addressed such as physical alteration of antenna parts via a rotational motion. This technique is supported by software to achieve a complete controlled rotatable reconfigurable cognitive radio antenna system. The inter-correlation between neural networks and cellular automata is also addressed for the design of reconfigurable and multi-band antenna systems for various applications.\u2

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Analysis and Synthesis of Magnetically Negative (MNG) Material using Softcomputing Techniques

Unique properties of Metamaterial are widely used in Electromagnetic Engineering, and the metamaterial has gained significant attention to be a major research area. Some of its recent research areas are carpet cloaking and metasurface design. The unique properties of these materials include simultaneous negative electromagnetic property, i.e., both permeability and permittivity are negative, because of which a negative refractive index is generated.Thus there are three primary classes of metamaterials. When only the permittivity is negative, the material is called ENG (Electrical Negative). Similarly material with only negative permeability is known as MNG (Magnetic Negative). Further when both are negative the material is regarded as DNG (Double Negative). Out of these three, the analysis and synthesis of MNG is very complicated and difficult. Therefore, the focus in this work is only on MNG, and the word "metamaterial" refers to MNG unless otherwise mentioned specifically. These type of materials don’t occur in nature and hence manufactured by making array of small unit cells of specific structure(s) made up of conductors. Although the concept of the existence of negative refractive index was proposed in the 1960s by Veselago, it took around 40 years to be verified practically when smith et al. did the experiment in 2001. They used an array of unit cell structures as Split-Ring-Resonators (SRR) and thin wires to verify the concept. Thereafter researchers are working to develop different forms of metamaterial unit cells and for which metamaterial is still an open area of research. However, while designing a metamaterial unit cell, absence of an empirical formula makes the model analysis and synthesis difficult. Although with the help of EM simulation tools this is possible, it usually is too difficult, time consuming and costly. Due to this researchers are motivated to look for alternative methods. In this work, some techniques to develop CAD models are presented based on soft computing techniques for metamaterial analysis and synthesis. Use of different soft computing techniques in the field of microwave engineering is documented in the literature. However, unconventional unit cell structures are difficult to analysis because of unavailability of predefined mathematical formulas and equivalent analysis. This can be done by the complex Modified Nicolson-Ross-Weir (NRW) method with the support of EM simulation tools which are expensive. Frequency dependency of metamaterial characteristics for any kind of unit cell structure follows a similar pattern which is obtained from Lorentz model. The basic idea in this work, which develops CAD Models for metamaterial unit cell of unconventional structures is based on the assumption that each type of unit cell can be mapped to an equivalent SRR structure, for which empirical formula is available. This is done by implementing the concept of Space Mapping technique or surrogate based modeling. Most important contribution of the work is the development of Space Mapped CAD model for analysis of an Ω atom. The developed model is validated with a Deformed-Ω atom, which is developed by integrating the concept of Space Mapping (SM) and Artificial Neural Network. Thereafter, the work progresses with proposing CAD models for synthesis of SRR. The objective is to find the design parameters of SRR for a desired material characteristic and frequency. With the availability of only a complex non-linear analysis formula, the synthesis becomes a reverse engineering problem, which is difficult to process. Three different models are proposed to solve the problem. The first approach is use of Inverse Artificial Neural Network concept, which uses a trained neural network (IANN) to perform output-to-input mapping. The developed CAD model using this approach includes integration of three concepts: IANN, Prior Knowledge Input-Difference (PKI-D) and SM. Although the model is capable of synthesizing a metamaterial unit cell, still it has some disadvantages. To overcome the disadvantages (such as lower convergence rate, lower accuracy and complex programming), use of Evolutionary Algorithms (Genetic Algorithm and Differential Evolution) is proposed. While developing CAD model based on EA, the methodology is first tested by synthesizing Rectangular Microstrip Antenna (RMPA) and then using the same concept, an SRR is synthesized. A comparison shows DE based model to be more efficient than IANN and GA based models in terms of convergence speed, accuracy and robustness

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium