Antenna is a key component in wireless devices such as cell phones, laptops and smartwatches. With the new generation of Wi-Fi technology: Wi-Fi 6E coming out, 1200MHz bandwidth from 5.925GHz to 7.125GHz is freed for use. Mobile devices are expected to meet the required bandwidth allocated for Wi-Fi 6E. However, electrically small antenna design for Wi-Fi 6 and 6E applications has been a challenge. Reducing the size of antennas while maintaining the performance is one major issue. The goal of this project is to evaluate different antennas and try to find the potential compact antenna that could cover Wi-Fi 6 and Wi-Fi 6E bands. In this project, we evaluated different types of electrically small antennas, explored parameters that affect antenna performance, characterized one nominated antenna in High Frequency Simulation Software(HFSS), prototyped the antenna in Altium Designer and measured the antenna performance using Network Analyzer. The measurement result shows that the proposed antenna is omni-directional, partially meet the fixed frequency requirement and has low efficiency at 2.4GHz but good efficiency at 6GHz bands. The conclusion is that the proposed antenna is good for the extended bandwidth of Wi-Fi 6 but for the whole Wi-Fi 6E the performance still needs to be improved in future work. / Antenn är en nyckelkomponent i trådlösa enheter som mobiltelefoner, bärbara datorer och smartklockor. Med den nya generationens Wi-Fi-teknik: Wi-Fi 6E kommer ut, 1200MHz bandbredd från 5,925GHz till 7,125GHz frigörs för användning. Mobila enheter förväntas uppfylla den erforderliga bandbredden som tilldelats för Wi-Fi 6E. Däremot har en elektrisk liten antenndesign för Wi-Fi 6 och 6E-applikationer varit en utmaning. Att minska storleken på antennerna samtidigt som prestandan bibehålls är en stor fråga. Målet med detta projekt är att utvärdera olika antenner och försöka hitta den potentiella kompakta antennen som kan täcka Wi-Fi 6- och Wi-Fi 6E-banden. I det här projektet utvärderade vi olika typer av elektriskt små antenner, utforskade parametrar som påverkar antennprestanda, karakteriserade en nominerad antenn i High Frequency Simulation Software (HFSS), prototypade antennen i Altium Designer och mätte antennens prestanda med hjälp av Network Analyzer. Mätresultatet visar att den föreslagna antennen är rundstrålande, delvis uppfyller kravet på fast frekvens och har låg verkningsgrad vid 2,4GHz men bra effektivitet vid 6GHz-band. Slutsatsen är att den föreslagna antennen är bra för den utökade bandbredden för Wi-Fi 6 men för hela Wi-Fi 6E behöver prestandan fortfarande förbättras i framtida arbete.

<p>Validerat; 20101217 (root)</p>

<p>Radon is a hazardous substance that cannot be perceived by our senses. It has long been known that exposure to high radon levels for a long period of time will ultimately cause lung cancer. The Swedish Radiation Safety Authority estimates that 500 people die annually due to this. Although most of them are smokers, even non-smokers suffer from lung cancer caused by radon. The statutory value for radon in homes today is 200 Bq/m³. Several years of research points to the fact that 63% of all those who develop lung cancer have been exposed to radon levels between 100-200 Bq/m³. This is why the WHO has lowered the recommended value to  100 Bq/m³,  and The Radiation Safety Authority of Sweden also has the same recommendation today. This study has been rendered to the Municipality of Eskilstuna, and its environmental and emergency management. The study has identified 72 % of the rental properties for radon measurements and action through personal visits to 14 large and medium-sized property managers in Eskilstuna. Several conclusions can be made from the study. Generally, very few measurements have been made and these have shown 6 % of high radon levels. The various property managers are at very different levels regarding their work with radon and there are very big differences amongst them as regards giving priority to the issue with radon. In 2020, the Swedish parliament has decided that no one should be exposed to radon levels above 200 Bq/m³ in their homes. Today there is legislation that applies against radon in apartment buildings as well as effective methods to reduce radon levels. However, the problem is instead the fact that there is a lack of resources at hand for the public health inspectors. Consequently, it seems rather impossible achieving the goal set for 2020. Thus it is of utmost interest to highlight this problem for the politicians that ultimately set the budget for the services in the municipality.</p>

Radon is a hazardous substance that cannot be perceived by our senses. It has long been known that exposure to high radon levels for a long period of time will ultimately cause lung cancer. The Swedish Radiation Safety Authority estimates that 500 people die annually due to this. Although most of them are smokers, even non-smokers suffer from lung cancer caused by radon. The statutory value for radon in homes today is 200 Bq/m³. Several years of research points to the fact that 63% of all those who develop lung cancer have been exposed to radon levels between 100-200 Bq/m³. This is why the WHO has lowered the recommended value to  100 Bq/m³,  and The Radiation Safety Authority of Sweden also has the same recommendation today. This study has been rendered to the Municipality of Eskilstuna, and its environmental and emergency management. The study has identified 72 % of the rental properties for radon measurements and action through personal visits to 14 large and medium-sized property managers in Eskilstuna. Several conclusions can be made from the study. Generally, very few measurements have been made and these have shown 6 % of high radon levels. The various property managers are at very different levels regarding their work with radon and there are very big differences amongst them as regards giving priority to the issue with radon. In 2020, the Swedish parliament has decided that no one should be exposed to radon levels above 200 Bq/m³ in their homes. Today there is legislation that applies against radon in apartment buildings as well as effective methods to reduce radon levels. However, the problem is instead the fact that there is a lack of resources at hand for the public health inspectors. Consequently, it seems rather impossible achieving the goal set for 2020. Thus it is of utmost interest to highlight this problem for the politicians that ultimately set the budget for the services in the municipality.

A black body is an ideal object that absorbs all incident electromagnetic radiation and simultaneously emits radiation that only depends on the temperature. The radiation is described by Planck's radiation law and its maximum by Wien's displacement law. The aim of this project is to study Planck's and Wien's laws in the frequency and wavelength domains, by theoretical studies and numerical studies in the programming language Python. Planck's law can be derived by regarding a cavity where the internal radiation either can be regarded as waves or as a gas of photons. In this study, the main focus lies in the derivation assuming radiation can be treated as waves, which uses the Maxwell-Boltzmann distribution. This derivation is also used when the radiation is simulated numerically in Python. The numerical studies use the stochastic method "hit and miss" to generate the different properties of the emitted radiation. Planck's law occurs in many different forms, the differences between some of them is explained in this project. When transforming between the domains one must use a Jacobian. If this is forgotten Wien's law, which is derived from Planck’s law, efficiently shows how the peaks of the correct and the transformed curves are at different positions. The results show that Planck's law accurately can be derived numerically. Even though the chosen method successfully reproduces the Planck distribution the program can be improved by using the inverse transform method for sampling. To study this subject further one could consider deriving and simulating the Maxwell-Boltzmann distribution. / En svart kropp är intressant att undersöka på grund av dess unika förmåga att absorbera och emittera elektromagnetisk strålning. Dessvärre kan den svarta kroppen vara svår att föreställa sig. Det vedertagna knepet för att illustrera detta fenomen är att tänka sig en låda inuti vilken det finns fotoner, och därmed energi. Fotoner kan som bekant betraktas som vågor likväl som partiklar och turligt nog spelar det ingen roll vilket sätt man väljer, svartkroppsstrålningen kan studeras ur båda dessa infallsvinklar. Tänker man sig också att det finns ett mycket litet hål i lådans vägg är det lätt att inse att fotonerna kommer att lämna lådan ur detsamma. Det är denna strålning som är svartkroppsstrålning. Svartkroppsstrålningen är fördelad enligt Plancks strålningslag som vanligtvis härleds med hjälp av teorin kring statistisk fysik som appliceras på den tänkta lådan. Detta görs även i denna studie, såväl som en numerisk simulering i programmeringsspråket Python. Ett program för studier av svartkroppsstrålning, vars främsta syfte är att simulera denna med utgångspunkt i samma låda, har skapats och förväntas kunna hjälpa den intresserade att skaffa sig förståelse för egenskaperna hos Plancks lag. För detta program används med framgång den stokastiska metoden "hit and miss" som tillåter användaren att sampla slumptal från en given fördelning. Utöver Plancks lag studeras också Wiens lag. Wiens lag beskriver vid vilken frekvens strålningen kommer att ha sitt maximum och härleds ur Plancks lag. Plancks lag förekommer i många olika former vilka beskriver olika fysikaliska storheter. I denna studie utreds dessa. Att transformera mellan de olika formerna av lagen är inte så simpelt som man kan luras att tro, utan kräver viss matematisk eftertanke. Det visar sig vara avgörande att använda en mycket viktig transformationsfaktor kallad Jacobian. Detta ger såklart också konsekvenser för Wiens lag som kommer att se olika ut beroende på vilken form av Plancks lag den härleds ur.