Radio Astronomers demand for highly sensitive astronomical facility. Their demand is a radio telescope that can detect the weakest and deepest radio signal. To fulfill the demand of high sensitive telescope, an entirely new way of realizing a radio telescope is required. One of the most important components in the RF front end that determines the sensitivity of a radio telescope is the Low Noise Amplifier (LNA). The project has the selected process technologies which was searched and about the different noise matching topologies, input matching topology, wide band noise and input matching topologies has discussed by the author to the requirement of LNA in Astronomical purposes. In this report, the best process technology candidate was chosen apart from selected technology candidates to obtain the minimum noise temperature over broad range frequency upon the modern era of Astronomical LNAs. The work was continued to design a single ended LNA to obtain desired transistor parameters while using different noise matching topologies, input matching topologies, wideband noise and input matching topologies to have an LNA achievement with the design goal. Further two stage amplifier was implemented to obtain minimum noise temperature, good stability, high gain, good input and output reflection coefficient with less power consumption.

This report is a master degree thesis in electronics that examines if weak relations can be used in TracFeed. TracFeed is a simulation tool designed to aid in the dimensioning of the power supply system for electrical railroads. The program was originally developed by Adtranz and is today further enhanced by Balfour Beatty Rail AB. When using weak relations there will be fewer truncations of the steps and therefore the response time will decrease. The purpose of this thesis is to study how much time that can be gained in different types of simulations and in which way the result is effected because of weak relations. The theoretical part explains the fundamentals concerning electrical trains and how trains are modelled in TracFeed. The calculation kernel used by TracFeed is called SIMPOW and it is described as well as the modelling language which is used to create the train models. Weak relations are tested in two simulations. The result from those simulations shows that if a displacement in simulated time of the output is acceptable and there are many trains active simultaneously weak relations are an interesting alternative.

Progress in CMOS technology and in fine pitch bump bonding has made possible the development of high granularity single photon counting detectors for X-ray imaging. This thesis studies the design and characterization of three pulse processing chips with 65536 square pixels of 55 μm x 55 μm designed in a commercial 0.25 μm 6-metal CMOS technology. The 3 chips share the same architecture and dimensions and are named Medipix2, Mpix2MXR20 and Timepix. The Medipix2 chip is a pixel detector readout chip consisting of 256 x 256 identical elements, each working in single photon counting mode for positive or negative input charge signals. The preamplifier feedback provides compensation for detector leakage current on a pixel by pixel basis. Two identical pulse height discriminators are used to define an energy window. Every event falling inside the energy window is counted with a 13-bit pseudo-random counter. The counter logic, based in a shift register, also behaves as the input/output register for the pixel. Each cell also has an 8-bit configuration register which allows masking, test-enabling and 3-bit individual threshold adjust for each discriminator. The chip can be configured in serial mode and readout either serially or in parallel. Measurements show an electronic noise ~160 e- rms with a gain of ~9 mV/ke-. The threshold spread after equalization of ~120 e- rms brings the full chip minimum detectable charge to ~1100 e-. The analog static power consumption is ~8 μW per pixel with Vdda=2.2 V. The Mpix2MXR20 is an upgraded version of the Medipix2. The main changes in the pixel consist of: an improved tolerance to radiation, improved pixel to pixel threshold uniformity, and a 14-bit counter with overflow control. The chip periphery includes new threshold DACs with smaller step size, improved linearity, and better temperature dependence. Timepix is an evolution of the Mpix2MXR20 which provides independently in each pixel information of arrival time, time-over-threshold or event counting. Timepix uses as a time reference an external clock (Ref_Clk) up to 100 MHz which is distributed all over the pixel matrix during acquisition mode. The preamplifier is improved and there is a single discriminator with 4-bit threshold adjustment in order to reduce the minimum detectable charge limit. Measurements show an electrical noise ~100 e- rms and a gain of ~16.5 mV/ke-. The threshold spread after equalization of ~35 e- rms brings the full chip minimum detectable charge either to ~650 e- with a naked chip (i.e. gas detectors) or ~750 e- when bump-bonded to a detector. The pixel static power consumption is ~13.5 μW per pixel with Vdda=2.2 V and Ref_Clk=80 MHz. This family of chips have been used for a wide variety of applications. During these studies a number of limitations have come to light. Among those are limited energy resolution and surface area. Future developments, such as Medipix3, will aim to address those limitations by carefully exploiting developments in microelectronics. / Framstegen inom CMOS-teknologin och tekniken för bump bondning har möjliggjort utveckling av högupplösande bilddetektorer för detektering av enskilda röntgenfotoner eller laddade partiklar. Denna avhandling behandlar design och karakterisering av tre pulsräknande utläsningskretsar med 65536 kvadratiska bildelement med storleken 55 x 55 um2. De tre kretsarna, benämnda Medipix2, Mpix2MXR20 och Timepix, delar samma arkitektur och dimensioner. Medipix2 är en utläsningskrets för avbildning med 256 x 256 identiska bildelement som räknar enskilda fotoner utgående från positiva eller negativa laddningspulser. Förförstärkarens återkoppling kompenserar individuellt för läckströmmen i varje bildelement. Ett energifönster kan definieras med hjälp av två identiska diskriminatorkretsar. Varje händelse som faller inom energifönstret räknas i en 13-bitars pseudo-random räknare. Räknaren, utformad som ett skiftregister, fungerar också som in/utregister för varje bildelement. Kretsen kan läsas ut antingen seriellt eller parallellt. Det elektroniska bruset har uppmätts till ~160 e- rms vid en förstärkning av ~9 mV/ke-. Spridningen i tröskelspänning efter justering är ~120 e- rms vilket ger en minsta detekterbar laddningspuls över hela kretsen på ~1100 e-. Den statiska effektförbrukningen i del analoga delen är ~8 mW per bildelement vid Vdda=2,2 V. Mpix2MXR20 är en uppdaterad version av Medipix2. De huvudsakliga förändringarna är: bättre strålningshärdighet, jämnare tröskelvärden och en 14- bitsräknare med overflow. Periferin innehåller också nya DA-omvandlare med mindre steg, förbättrad linjäritet och mindre temperaturberoende. Timepix är en vidareutveckling av Mpix2MXR20 som medger detektering av ankomsttid, time-over-threshold eller pulsräkning individuellt i varje bildelement. Timepix utnyttjar en extern klocka (Ref_Clk) med frekvenser upp till 100 MHz som distribueras över hela bildmatrisen. Förförstärkaren är förbättrad och en enkel diskriminator med 4 bitars tröskeljustering används för att minimera lägsta detekterbara laddningspuls. Mätningar visar ett elektroniskt brus på ~100 e- rms och förstärkningen 16,5 mV/ke-. Med en tröskelspridning på 35 e- rms blir minsta detekterbara laddning för den nakna kretsen (t.ex. i en gasfylld detektor) ~650 eoch för en bondad detektor ~750 e-. Den statiska effektförbrukningen är ~13,5 mV per bildelement vid Vdda=2,2 V och Ref_Clk= 80 MHz. Den här kretsfamiljen har använts i ett antal olika applikationer. Under dessa studier har ett antal begränsningar konstaterats. Bland dessa märks begränsad energiupplösning och begränsad detektorarea. Framtida utvecklingsprojekt, t.ex. Medipix3, kommer att inriktas på att avhjälpa dessa begränsningar genom att utnyttja den senaste utvecklingen på mikroelektronikområdet.

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