الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
Due to the absence of application complications and processing, one option to diffuse antennas is to reconfigure cognitive radios to utilise the same antenna in both detecting and contact sensing. It’s also more popular (in comparison to other ways) because recipients don’t need to know which information is about the primary users. The output of the energy detector is compared to a threshold that counts above the noise floor to determine the signal. When deciding on the threshold for identifying primary users of the energy detector, there are numerous sensory problems, including the inability to identify between interference from main users and noise, as well as low performance during signal to noise ratio (SNR) revaluation. This thesis aims to design a tunable cognitive radio (CR) system based on the ultra-wide band. In this thesis, an antenna for cognitive radio that uses ultra-wideband spectrum sensing and a full energy detector is proposed (UWB). Cognitive radio (CR) can improve spectrum management, manage energy more effectively, and increase the flexibility of personal services using spectrum sensing. It provides a quick and low-cost method for locating spectrum holes ranging in frequency from 9.30 to 13 GHz. Frequency is scanned using a tunable ultra-wideband. One of the most essential technological requirements for the development of perceptual radio systems is spectrum sensing. The usage of a microstrip patch antenna in ultra-wideband applications is described. The antenna is small, with a ground of 30 mm × 30 mm and 5 gaps that are used as switches and measure 2 mm × 3 mm each. Switches are used to monitor the existence of the principal user (PU) and can offer adjusting capabilities. On a Rogers RT5880 substrate with a relative permittivity (εr) of 2.2, the recommended antenna is II constructed with a dielectric thickness of 1.575 mm. This sort of antenna has a number of benefits, including being flexible in terms of band accessibility, compact, cheap, easily produced, small in size, and simple in design. It is also made of copper. The presented low-VSWR antenna has the necessary radiation properties to satisfy the demands of present and upcoming wireless communications systems; toward the conclusion, both simulated and measured results are given.