RECONFIGURABLE MULTIBAND AND MULTIFUNCTIONAL RADIO-FREQUENCY INTEGRATED CIRCUITS

Abstract

merging optimal design approach for system-on-chip and system-in-package integration techniques has been based on cooperative co-design concept in which the effect of interactions between neighbouring components and die-package coupling has been taken into account and also some of the mono-functional components are designed together to achieve multi-functionality into a single component based on the cooperative design principle. The disadvantages with the conventional self-design approach are its design inefficiency, high losses, bandwidth reduction and space wasting. The concept of cooperative co-design has the advantages of improved design efficiency, lower losses, greater miniaturization, adaptability to components’ inherent properties, increased design flexibility and multi-functionality through component cooperation. Codesign philosophy for microwave integrated circuits realization includes the concept of multifunctional design or cooperative design. In a multifunctional design, two or more mono-functional circuits are integrated into a single component with multi-operational capability leading to improved overall system performance. Some of the examples of multifunctional RF circuits include filtering antenna, self-oscillating mixer, filtering power divider, filtering low-noise amplifier, filtering power amplifer, filtering balun, filtering coupler and active bandpass switchplexer. Multifunctional microwave circuits offer advantages of compact size, reduced power consumption, lower cost, reduced insertion loss, and enhanced overall RF performance of the multifunctional integrated system. In multifunctional RF circuit, functional integration is achieved through integration among individual RF components. It has been emerged as a promising solution for the microwave devices with improved performance. Reconfigurable multifunctional components find applications in reconfigurable softwaredefined opportunistic radio. Multifunctional multiband passive and active microwave circuits with reconfigurable capabilities find applications in next-generation software-defined cognitive radio (5G and enabling technology) and future wireless communication systems. Multiband RF circuits with added reconfigurable feature operate concurrently at multiple frequency bands and one or more bands can be individually or simultaneously tuned. For fulfilling the requirement of multiband and multistandard advanced wireless communication systems, concurrent multiband RF circuits with reconfigurable capabilities have been proved as a suitable candidate due to their potential for size and complexity reduction. Tunable ii multiband RF devices find applications in multiband software defined radio (SDR), carrier aggregation scheme in long-term evolution (LTE) service, and reconfigurable multiband/multistandard transceiver system. Fifth-Generation (5G) and future wireless communication technologies call for very high performance RF transceiver front-ends realized using integrated multifunctional approach with reconfigurable and multiband/multistandard capabilities. Reconfigurable concurrent multiband microwave circuits have not been sufficiently investigated so far and the design approaches for achieving adaptable multiband capabilities in RF circuits are not well established. The design approaches for electronically reconfigurable and concurrent multiband power divider/combiners, branch-line couplers, and low-noise amplifiers have not been extensively investigated and there is enough scope for developing concurrent multiband circuits with reconfigurable capabilities to reduce the power consumption, size, cost and complexity of the adaptable multiband transceiver front-ends required for next-generation and future wireless radio systems. Multiband multifunctional active RF components with adaptable operations have not been sufficiently studied, specifically the low-noise amplifier integrated with bandpass filter i.e. filtering LNA. Very less studies are available on the development of concurrent multiband filtering low-noise amplifier with reconfigurable capabilities. Extremely high level of integration offered by the multiband multifunctional active and passive microwave components with reconfigurable capabilities is required by the high performance RF transmitter and receiver front-ends for application in next-generation (5G) intelligent-radio (SDR) and future wireless communication systems. In view of above discussions, the research work presented in this thesis has been devoted to the development and characterization of reconfigurable multiband and multifunctional RF integrated circuits and its applications in industrial wireless sensors. Parametric sensing and environment detection using integrated approach is the key drivers for modern sensor technology. This thesis consists of seven chapters. The first chapter of the thesis gives a general introduction of reconfigurable multiband and multifunctional radio-frequency integrated circuits along with the motivation for carrying out this research work. iii A review on recent trends in the design of reconfigurable multiband and multifunctional active and passive RF circuits and its sensing applications has been presented in chapter-2 of the thesis. Research gaps, research objectives and thesis organizations are also included in this chapter. Development of varactor-tuned reconfigurable dualband bandpass filters, Wilkinson power dividers and branch-line couplers with less number of control voltages for passband reconfiguration has been described in chapter-3 of this thesis. Chapter 4 describes the development of dualband low-noise amplifiers with reconfigurable and filtering capabilities. A novel concurrent dualband LNA with reconfigurable and bandpass filtering capabilities have been designed, fabricated and characterized. Chapter 5 includes the development of reconfigurable oscillator and filtering antennas employed as subsystems in RF transmitter and receiver block for wireless pressure and temperature sensor applications. Chapter 6 of the thesis is devoted to the non-invasive wireless monitoring of pressure and temperature variations from a wireless range of 3.0-m for applications in gas/petrochemical/ water industry. Firstly, a wireless pressure monitoring system has been implemented using a block-level approach. Then, wireless pressure and temperature monitoring system using integrated approach has been developed and characterized. Some of the advantages of our proposed wireless sensor are its integrated design with customized subsystems, compact size, reduced cost, handheld, high pressure sensitivity response, good linearity response, increased flexibility and reliable for use in unfavorable temperature condition. Finally, the contribution of the thesis and future scope for carrying out further research work has been presented in chapter-7 of the thesis.