Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver

A Compact Dual-Band Negative Group Delay Microwave Circuit

A compact dual-band negative group delay circuit (NGDC) is proposed. The proposed NGDC is composed of an open-circuited transmission line and two resistors connected by two transmission lines. The frequency ratio is controlled by the characteristic impedance of the transmission lines. To verify the design concept, a dual-band NGDC with the frequency ratio of n = 2 (Circuit A) and a broadband NGDC with n = 1.16 (Circuit B) are designed and fabricated. The measured group delay value of the Circuit A is -1.19 ns at the center frequencies of lower and upper bands. And the measured NGD bandwidth is 34.6% for the lower band and 16.5% for the upper band, in which the return loss and insertion loss are better than 16.9 dB and 18.2 dB, respectively. From the measurement results of Circuit B, a flat fractional NGD bandwidth of 19.8% with GD of (-1.58 ± 0.13) ns is obtained, in which the return loss and insertion loss are better than 23 dB and 32.5 dB, respectively

Compact and Efficient Millimetre-Wave Circuits for Wideband Applications

Radio systems, along with the ever increasing processing power provided by computer technology, have altered many aspects of our society over the last century. Various gadgets and integrated electronics are found everywhere nowadays; many of these were science-fiction only a few decades ago. Most apparent is perhaps your ``smart phone'', possibly kept within arm's reach wherever you go, that provides various services, news updates, and social networking via wireless communications systems. The frameworks of the fifth generation wireless system is currently being developed worldwide. Inclusion of millimetre-wave technology promise high-speed piconets, wireless back-haul on pencil-beam links, and further functionality such as high-resolution radar imaging. This thesis addresses the challenge to provide signals at carrier frequencies in the millimetre-wave spectrum, and compact integrated transmitter front-ends of sub-wavelength dimensions. A radio frequency pulse generator, i.e. a ``wavelet genarator'', circuit is implemented using diodes and transistors in III--V compound semiconductor technology. This simple but energy-efficient front-end circuit can be controlled on the time-scale of picoseconds. Transmission of wireless data is thereby achieved at high symbol-rates and low power consumption per bit. A compact antenna is integrated with the transmitter circuit, without any intermediate transmission line. The result is a physically small, single-chip, transmitter front-end that can output high equivalent isotropically radiated power. This element radiation characteristic is wide-beam and suitable for array implementations

A Compact Negative Group Delay Microstrip Diplexer with Low Losses for 5G Applications: Design and Analysis

Microstrip Diplexers play an important role in modern wireless communication systems. In this paper, a novel compact microstrip diplexer based on spiral cells is presented. The proposed resonator primarily consists of two spiral thin lines connected to a pair of coupled lines. This novel resonator is analyzed mathematically to find its behavior and tune the dimensions of the final layout easily. Using the analyzed resonator, two bandpass filters (BPFs) are designed. Then, a novel high-performance microstrip diplexer is obtained by designing and integrating these two BPFs. The center frequencies of the first and second channels of the proposed diplexer are 1.86 GHz and 4.62 GHz, respectively. The proposed diplexer boasts a remarkably small size of 0.004 λg2 and features flat channels with low insertion losses of only 0.048 dB and 0.065 dB for the first and second channels, respectively. The maximum group delays of S21 and S31 are 0.31 ns, 0.86 ns, respectively, which are good values for a modern communication system. Meanwhile, inside its passbands for some frequency ranges, its group delays are negative. Thus, using this diplexer can decrease the signal dispersion. The 1st and 2nd passbands are wide with 47.3% and 47.1% fractional bandwidths (FBW), respectively. Therefore, this diplexer can be easily and successfully used in designing high-performance RF communication systems

Impedance Transformers

Non

A Compact RF/Photonic Antenna using a Quantum Dot Mode Locked Laser as a Source

The research presented here is focused on achieving an active compact RF/Photonic antenna module based on a broadband antenna design integrated with a quantum dot mode-locked laser (QDMLL). A two-section QDMLL is used to produce pulsed microwaves signals to feed the radiating antenna. To realize the microwave signal radiation generated by the QDMLL, several possible MLL-integrated-antennas are proposed. The prototype integrated antenna is fully described, including the design, fabrication, and characterization of the antenna performance. Additionally, this work deals with the improvement of the radiation efficiency and functionality of the integrated module. An impedance matching network is designed to match the QDMLL to a bowtie slot antenna. The RF/Photonic integrated prototype is tested and analyzed over a wide frequency range. Finally a QDMLL-integrated-phased antenna array is designed to achieve beam steering. By manipulating the applied voltage bias of each QDMLL, one can achieve beam steering without the use of external RF phase shifters yielding a more compact design of an RF/photonic antenna on a chip. The 2-element integrated prototype is presented and discussed. Beam-steering is fully demonstrated via both simulation and measurements

Microstrip post production tuning bar error and compact resonators using negative refractive index metamaterials

In this thesis, two separate research topics are undertaken both in the general area of compact RF/microwave circuit design. The first topic involves characterizing the parasitic effects and error due to unused post-production tuning bars. Such tuning bars are used in microwave circuit designs to allow the impedance or length of a microstrip line to be adjusted after fabrication. In general, the tuning bars are simply patterns of small, isolated sections of conductor adjacent to the thru line. Changing the impedance or length of the thru line involves bonding the appropriate tuning bars to the line. Unneeded tuning bars are simply not removed and left isolated. Ideally, there should be no coupling between these unused tuning bars and the thru line. Therefore, the unused tuning bars should have a negligible effect on the circuit??s overall performance. To nullify the parasitic effects of the tuning bars, conventional wisdom suggests placing the bars 1.0 to 1.5 substrate heights away from the main line. While successful in the past, this practice may not result in the most efficient and cost-effective placement of tuning bars in today??s compact microwave circuits. This thesis facilitates the design of compact tuning bar configurations with minimum parasitic effects by analyzing the error attributable to various common tuning bar configurations with a range of parameters and offset distances. The error is primarily determined through electromagnetic simulations, and the accuracy of these simulations is verified by experimental results. The second topic in this thesis involves the design of compact microwave resonators using the transmission line approach to create negative refractive index metamaterials. A survey of the major developments and fundamental concepts related to negative refractive index technology (with focus on the transmission line approach) is given. Following is the design and measurement of the compact resonators. The resonators are also compared to their conventional counterparts to demonstrate both compactness and harmonic suppression