Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016. / Optimum communication can only be achieved with a very sensitive front-end section in the receiver on a satellite because the transmitted signal from the ground station must travel hundreds of kilometres through the earth's atmosphere to a low earth orbit (LEO) satellite. This dissertation presents the design of the front end section of the receiver suitable for use in a nano-satellite. Specifically, various transistor technologies are evaluated by designing five low noise amplifiers to determine the optimum performing amplifier. The bandwidth of the front end section was controlled by designing coupled line microstrip filter. For consistency, the same design technique was followed in the design of each LNA. Simulations were performed and the results were compared to the actual measured results of the constructed amplifiers to facilitate conclusions to be made. Design specifications for the LNAs were obtained from the F'SATI Space CubeSat Programme Technical Specification document. To control the bandwidth of the front end section, various types of band-pass filters were investigated, resulting in a coupled line band-pass filter being simulated and implemented. The simulated results were compared to the measured results of the constructed filter. In the final stage of this dissertation, comparisons of each amplifier’s performance were made, resulting in the final recommendation for this project.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 69-72). Also available on the World Wide Web.

This thesis deals with two kinds of RF CMOS low noise amplifiers (LNA). The low power LNA and the image-reject LNA. The impact of gain, noise figure, and stability on RF CMOS image-reject LNA has been studied. Through this study, the fundamental properties of image-reject LNA can be understood by a simple but physical concept. A current-reuse RF CMOS source-degenerated cascode LNA is also presented, which adopts a combination of source-degenerated NMOS inverter and Cascode topology to improve gain and noise figure, the existent and well-studied technique from the design standpoint, makes optimization of the stage easy. A modification of the proposed architecture is also presented, which adopts internal filters to achieve the image rejection without additional image-reject filters that degrade both noise figure and power consumption. It will be a good candidate for low power implementation of CMOS RF-IC. Both circuits¡¦ parameters except noise figures are simulated using TSMC 0.25 um RF CMOS component models. The noise models considered here include induced gate noise, thermal noise and shot noise [5]. The current-reuse source-degenerated NMOS inverter LNA noise figure is 0.7 dB, forward gain is 16 dB, and IIP3 is -15 dBm. The low power image-reject LNA noise figure is 0.7 dB, forward gain is 16 dB, IIP3 is -16 dBm, and image rejection is 20 dB at 1.6 GHz. Both LNAs operate at 2.4 GHz and consume about 6 mA under a 2.5 V voltage supply.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 68-70). Also available on the World Wide Web.

Thesis (Ph.D.)--Victoria University (Melbourne, Vic.), 2009.

Low-noise operational amplifiers are an important tool in the life sciences. Biosensor measurements typically rely on low-noise transimpedance amplifiers to record biological signals. Two different techniques were used to leverage the advantages of low-noise circuitry for bioelectronics. A CMOS-integrated system for measuring redox-active substrates using electrochemical read-out at very low noise levels is presented. The system incorporates 112 amplifier channels capable of current sensing with noise levels below 1 fArms in a 3.5-Hz bandwidth. The amplifier is externally connected to a gold microelectrode with a radius of 15 µm. The amplifier enables measurement of redox-couples such as potassium ferrocyanide/ferricyanide with concentrations down to 10 nM at current levels of only 300 fA. The electrochemical noise that sets the limits of detection is also measured and analyzed based on redox mass transfer equation and electrochemical impedance spectroscopy. Secondly, CMOS-integrated low noise junction field-effect transistors (JFETs) were developed in a standard 0.18-µm CMOS process. These JFETs reduce input referred flicker noise power by more than a factor of 10 when compared with equally sized n-channel MOS devices by eliminating oxide interfaces in contact with the channel. We show that this improvement in device performance translates into a factor-of-10 reduction in the input-referred noise of integrated CMOS operational amplifiers when JFET devices are used at the input.

Στην εργασία αυτή περιγράφεται η διαδικασία σχεδίασης ενός ενισχυτή χαμηλού θορύβου, ο οποίος αποτελεί το πιο κρίσιμο κομμάτι ενός δέκτη υψηλών συχνοτήτων όσον αφορά τη θορυβική συμπεριφορά. Η μέθοδος εφαρμόζεται στη σχεδίαση ενός ενισχυτή χαμηλού θορύβου στη συχνότητα των 1.42 GHz, ο οποίος θα αποτελέσει το πρώτο στάδιο του δέκτη ενός ραδιοτηλεσκόπιου. Τέλος σχεδιάζεται η πλακέτα πάνω στην οποία υλοποιείται ο ενισχυτής και παρουσιάζονται τεχνικές μέτρησης πολύ χαμηλού θορύβου. / In this thesis a methodology for the design of a Low Noise Amplifier is described. This amplifier consists the most critical part of a Radio Frequency receiver regarding the noise performance. The method is applied to the design of a low noise amplifier at the frequency of 1.42GHz, which will be the first stage of a radio telescope receiver. At the end, the printed circuit board of the amplifier is designed and very low noise measurement techniques are presented.

Submitted in fulfillment of the academic requirements for the Master’s Degree of Technology: Electrical Engineering – Light Current, Durban University of Technology, 2012. / The development of a transit radio telescope at the hydrogen line frequency of 1420 MHz is described. The telescope antenna uses a 5 m diameter parabolic reflector with an estimated efficiency of 50 % and an F/D ratio of 0.5. The gain of the antenna at 1420 MHz (wavelength of 21.1 cm) is approximately 35 dB with a beamwidth of approximately 3°. The antenna is mounted on a concrete beam at the first floor level, running between two 5 floor tower blocks on the Steve Biko campus of the Durban University of Technology. The majority of the components of the radio telescope antenna and receiver were designed and manufactured at the Durban University of Technology by students of the Departments of Mechanical and Electronic Engineering. The measured sensitivity of the receiver is approximately -94 dBm with a bandwidth of approximately 80 MHz. Radio sources successfully detected by the radio telescope include the Sun, the Moon, Sagittarius A, Centaurus A and Vela X.

Full integration of CMOS low noise amplifiers (LNA) presents a challenge for low cost CMOS receiver systems. A critical problem faced in the design of an RF CMOS LNA is the inaccurate high-frequency noise model of the MOSFET implemented in circuit simulators such as SPICE. Silicon-based monolithic inductors are another bottleneck in RF CMOS design due to their poor quality factor. In this thesis, a CMOS implementation of a fully-integrated differential LNA is presented. A small-signal noise circuit model that includes the two most important noise sources of the MOSFET at radio frequencies, channel thermal noise and induced gate current noise, is developed for CMOS LNA analysis and simulation. Various CMOS LNA architectures are investigated. The optimization techniques and design guidelines and procedures for an LC tuned CMOS LNA are also described. Analysis and modeling of silicon-based monolithic inductors and transformers are presented and it is shown that in fully-differential applications, a monolithic transformer occupies less die area and achieves a higher quality factor compared to two independent inductors with the same total effective inductance. It is also shown that monolithic transformers improve the common-mode rejection of the differential circuits. / Graduation date: 1999

Στη διπλωματική αυτή εργασία περιγράφεται η σχεδίαση και η υλοποίηση σε πλακέτα (PCB) ενός Ultra Wideband Low Noise Amplifier (UW-LNA) με περιοχή λειτουργίας 3.1- 10.6 GHz. Ο ενισχυτής αυτός αποτελεί το σημαντικότερο κομμάτι ενός δέκτη σε ό,τι α- φορά τη θορυβική συμπεριφορά του τελευταίου. / In this diploma thesis we designed an Ultra Wideband Low Noise Amplifier (UW-LNA), operating in the band of frequencies between 3.1-10.6 GHz. The LNA has also been implemented on a PCB. The LNA is the most important component of a receiver as far as the noise behavior is concerned.