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Over the past decade, there has been a significant increase in the need for multi-functional antenna designs, driven by stringent design prerequisites in wireless systems. Simultaneously, different challenges arise because of the requirements for the antenna module in limited design space. Electromagnetic simulation of parametric changes in traditional patch antennas generally result in sub-optimal designs due to topological complexity. In this thesis, novel systematic approaches to design pixelated antennas to support multistandard wireless application have been presented. Firstly, a low-profile dual-band pixelated defected ground antenna has been proposed. The design introduces the idea of utilizing pixelated defected ground for efficient antenna design without depending on geometric optimization of design parameters of defected ground area, unlike conventional defected ground antenna. Compact antenna design can be achieved by making the best use of designated design space on the defected ground plane. Secondly, a systematic approach to achieve optimal design of a Pixelated Stacked Antenna has been presented. The antenna design uses pixelization on the two radiating patches to enable simultaneous optimization of multiple layers, resulting in improved optimization balance. The design methodology utilizes a combination of triangular and square pixel shapes where triangular-shaped pixels are used to form the principal radiating patch, and square-shaped pixels are implemented on the stacked parasitic patch. Thirdly, a pixelated cubic antenna with enhanced isolation and diverse radiation pattern has been presented. The issue of mutual coupling comes into effect when multiple antenna elements are closely placed together. The presented antenna system with four patches has been pixelated and optimized simultaneously to achieve desired performance and high isolation without using any additional resonators or elements. Finally, a novel approach to increasing bandwidth in lo

type:Journal Article, Microwave imaging is the technique to identify hidden objects from structures using electromagnetic waves that can be applied in medical diagnosis. The change of dielectric property can be detected using microwave antenna sensor, which can lead to localization of abnormality in the human body. This paper presents a stacked type modified Planar Inverted F Antenna (PIFA) as microwave imaging sensor. Design and performance analysis of the sensor antenna along with computational and experimental analysis to identify concealed object has been investigated in this study. The dimension of the modified PIFA radiating patch is 40 × 20 × 10 mm3. The reflector walls used, are 45 mm in length and 0.2-mm-thick inexpensive copper sheet is considered for the simulation and fabrication which addresses the problems of high expenses in conventional patch antenna. The proposed antenna sensor operates at 1.55–1.68 GHz where the maximum realized gain is 4.5 dB with consistent unidirectional radiation characteristics. The proposed sensor antenna is used to identify tumor in a computational human tissue phantom based on reflection and transmission coefficient. Finally, an experiment has been performed to verify the antenna’s potentiality of detecting abnormality in realistic breast phantom.

type:Journal Article, One of the most efficient methods to observe the impact of geographical, environmental, and geological changes is remote sensing. Nowadays, nanosatellites are being used to observe climate change using remote sensing technology. Communication between a remote sensing nanosatellite and Earth significantly depends upon antenna systems. Body-mounted solar panels are the main source of satellite operating power unless deployable solar panels are used. Lower ultra-high frequency (UHF) nanosatellite antenna design is a crucial challenge due to the physical size constraint and the need for solar panel integration. Moreover, nanosatellite space missions are vulnerable because of antenna and solar panel deployment complexity. This paper proposes a solar panel-integrated modified planner inverted F antenna (PIFA) to mitigate these crucial limitations. The antenna consists of a slotted rectangular radiating patch with coaxial probe feeding and a rectangular ground plane. The proposed antenna has achieved a −10 dB impedance bandwidth of 6.0 MHz (447.5 MHz–453.5 MHz) with a small-sized (80 mm× 90 mm× 0.5 mm) radiating element. In addition, the antenna achieved a maximum realized gain of 0.6 dB and a total efficiency of 67.45% with the nanosatellite structure and a solar panel. The challenges addressed by the proposed antenna are to ensure solar panel placement between the radiating element and the ground plane, and provide approximately 55% open space to allow solar irradiance into the solar panel.

type:Journal Article, A compact UHF antenna has been presented in this paper for nanosatellite space mission. A square ground plane with slotted rectangular radiating element have been used. Coaxial probe feeding is used to excite. The rectangular slot of the radiating patch is responsible for resonating at lower UHF bands. One of the square faces of the nanosatellite structure works as the ground plane for the slotted radiating element. The fabricated prototype of the proposed antenna has achieved an impedance bandwidth (S11< -10dB) of 7.0 MHz (398 MHz– 405 MHz) with small size of 97 mm× 90 mm radiating element. The overall ground plane size is 100 mm × 100 mm × 0.5 mm. The proposed antenna has achieved a gain of 1.18 dB with total efficiency of 62.5%. The proposed antenna addresses two design challenges of nanosatellite antenna, (a) assurance of the placement of solar panel beneath the radiating element; (b) providing about 50% open space for solar irradiance to pass onto the solar panel, enabling the solar panel to achieve up to 93.95% of power under of normal conditions.