Microwave substrate filter implementationfor an advanced 5G antenna system

Sammanfattning: This master thesis has been done at Ericsson AB (2018) in collaboration with LeonardoPadial Torán. Microwave filters for the future 5G have become an increasingly interesting researchtopic. The conventional design theory of microwave filters is no longer valid. Newmodels have to be implemented that meet the challenges imposed by demands ofcompact size, low insertion losses, low cost and high performance.In this thesis work, stripline band pass filters with a 28 GHz center frequency havebeen designed and simulated for 5G wireless communication systems. Many designtechniques have been investigated in order to achieve the goal requirements and toovercome the design rules limitation. In particular two different filter categories havebeen designed and simulated:Uniform Impedance Resonator (UIR) configurations. There are various possibletopologies to implement UIR using stripline technology such as parallel-coupled,hairpin, interdigital and combined filters.Here, a parallel-coupled λ/2-line band pass filter was chosen and investigated by theinsertion loss method. This filter, however, displayed an undesired pass band at twicethe designed central frequency.Step Impedance Resonator (SIR) configurations. In order to suppress the secondharmonic, three different types of (SIR) band pass filters have been investigated: theparallel-coupled SIR filter, the hairpin SIR filter and, finally, a filter comprising fourcross-coupled hairpin SIR filters. Advanced Design System (ADS) has been used for the initial filter design and AnsysHFSS has been used for the electromagnetic (EM) simulation part, includingparameter optimization.