This report presents design concepts and experimental data of planar active antenna and quasi-optical power combining arrays with strong coupling to realize a compact and low-cost radar and communication system. The prototype circuits for this purpose were made in a layered configuration using microstrip lines and in a uniplanar structure using CPW's. As an active source, an FET was selected. As a unit cell of the power combining array, a single layered active antenna using microstrip lines and slots was fabricated. In the design, small signal S-parameters were used to determine the circuit configuration while a large signal analysis to the entire circuit involving the slot antenna input impedance was carried out. The circuit designed for 10 GHz was found to operate at 9.3 GHz and the other designed for 25 GHz at 24 GHz. In addition, the circuit with CPW's and slot designed for 10 GHz was found to operate at 8.6 GHz. Based on these successful results, linear power combining arrays were made. For the strong coupling, each oscillator output is connected by a single transmission line. Several 6-element microstrip arrays and a 4-element CPW array were fabricated. In the former, sharp main beams were obtained. To obtain a millimeter-wave operating frequency, the second harmonic spatial power combining array made with FET's were demonstrated around 40 GHz. To show a topology of a 2-dimensional array, a 16-element dual polarized array at 7.8 GEL was made. To obtain the maximum in-phase radiation signal, impedance matching, a phase of the radiation signal and a signal phase of each oscillator were taken into account ... Active antenna, Quasi-optical technique, Optical control, Spatial power combiner.

This book presents state-of-the-art trends in reconfigurable active and passive planar antennas and their applications in wireless communication systems operating in the frequency band 5-6 GHz. Due to various key features such as multifunction antenna design, compactness, planar nature, and low cost, these technologies are becoming popular for current and future wireless applications. This book discusses different novel antenna designs and their working principles in detail. The modern and future wireless systems require wideband antennas to accommodate various channels in a single band or in separate bands. The carrier aggregation (CA) has been introduced in the modern wireless systems such as LTE-advanced systems and 5G./6G. In CA, a device can use several channels for transmission and reception. The used channels can exist in the same frequency band (intra-band CA) or in distinct bands (inter-band CA). To accommodate more channels, more bandwidth is required within the operating band. For portable devices, circularly polarized (CP) antennas are more advantageous over linearly polarized antennas since in CP antennas, there is low risk of misalignment and, hence encountering interference. Circularly polarized antenna also provides higher link reliability for the portable devices. To provide high data rates, more bandwidth is needed to accommodate more channels. Various multifunction, compact, and wideband antennas for plethora of applications are addressed in detail in this book. The scope of developing reconfigurable active antennas for application in beam switching, beam steering, wireless charging, security systems, etc., is described. This book concludes by giving glimpses of antenna requirements for future wireless communication systems.

Electrical Engineering Active Antennas and Quasi-Optical Arrays Whether communications, radar, transportation, or defense drives your interest in solid-state devices at microwave and millimeter-wave frequencies, this ready reference book provides you with a useful review of quasi-optical power combining and active integrated antennas. Brought to you in one convenient volume are key reprinted papers from leading experts in microwave technology. Their valuable perspectives range from the most current advances to historical developments. Included as a special feature is an invited paper, never-before-published, which presents an overview of quasi-optical power combining by noted authority J. W. Mink and colleagues. You will discover other helpful highlighted topics such as: Transmitting and receiving active antennas Spatial power combining oscillators Spatial combining amplifiers Beam control Active integrated antennas and quasi-optical systems Analysis and CAD Emerging technologies—two dimensional quasi-optics

Provides systematic coverage of the theory, physics, functional designs, and engineering applications of advanced electromagnetic surfaces.

A detailed study of the science, engineering and applications of terahertz technology, based on room-temperature solid-state devices, which are seen as the key technology for wider applications in this frequency range. The relative merits of electronic and optical devices are discussed and new device principles identified. Issues of terahertz circuit design, implementation and measurement are complemented by chapters on current and future applications in communications, sensing and remote surveillance. Audience: The unique coverage of all aspects of terahertz technology will appeal to both new and established workers in the field, as well as providing a survey for the interested reader.

Do you want to know how to design high efficiency RF and microwave solid state power amplifiers? Read this book to learn the main concepts that are fundamental for optimum amplifier design. Practical design techniques are set out, stating the pros and cons for each method presented in this text. In addition to novel theoretical discussion and workable guidelines, you will find helpful running examples and case studies that demonstrate the key issues involved in power amplifier (PA) design flow. Highlights include: Clarification of topics which are often misunderstood and misused, such as bias classes and PA nomenclatures. The consideration of both hybrid and monolithic microwave integrated circuits (MMICs). Discussions of switch-mode and current-mode PA design approaches and an explanation of the differences. Coverage of the linearity issue in PA design at circuit level, with advice on low distortion power stages. Analysis of the hot topic of Doherty amplifier design, plus a description of advanced techniques based on multi-way and multi-stage architecture solutions. High Efficiency RF and Microwave Solid State Power Amplifiers is: an ideal tutorial for MSc and postgraduate students taking courses in microwave electronics and solid state circuit/device design; a useful reference text for practising electronic engineers and researchers in the field of PA design and microwave and RF engineering. With its unique unified vision of solid state amplifiers, you won’t find a more comprehensive publication on the topic.