Radiated RF Performance Measurements for 4G Mobile Termnals
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Radio Frequency (RF) measurements are a fundamental stage in the design, testing and optimization of radio systems. Different parameters are evaluated in order to ensure fulfillment of given design specifications. In addition to these, it has become mandatory for every manufacturer of RF equipment to comply with a set of specifications devised by regulatory entities in order to guarantee that different RF products will work together in an environment where deleterious interference among them is minimized. Mobile phones have emerged as perhaps the most emblematic and mass-produced RF devices to date. Nokia Corporation has a portfolio of smart devices known as Lumia phones. This thesis is part of a project carried out in this company in order to evaluate the performance of different RF parameters on such phones. Manufactures of RF devices have recently begun to evaluate RF parameters in a radiated manner by using a fairly straightforward setup that includes a radio communication tester, an RF shield box and an antenna coupler. This thesis provides a study on radiated RF measurements performed on 4G mobile terminals in the setup described above. Even though it may be presumed a similar study may already exist from other manufacturers, such information is rarely forthcoming due to confidentiality issues. Nokia Corporation has allowed the author to conduct such study in a way where the most fundamental principles of the measurement setup in question are highlighted and the RF performance of 4G phones is evaluated in that setup. The results presented herein include those obtained from measurements made in both the reactive and radiating near-field regions. I will establish the legitimacy of the results obtained in both regions, provided the phone is placed at an appropriate position, termed sweet spot. I propound three criteria to find that sweet spot. In order to verify the validity of my measurements, a process capability analysis will be conducted to demonstrate the compliance of the results to given specifications. An outline of the procedure to further verify the results is also presented at the end of the thesis. Finally, I will propose further investigations that may be derived from this thesis, from computational studies to a deeper analysis of uncertainties.