RF filter design, especially in 5g wireless networks, faces stress from the advancement of MIMO technology and its application with phased array technology. The necessary electromagnetic spectrums at work in RF and microwave designs make RF filters have to be that much more exact in their applications. Utilizing proper waveform and interference simulation within an EM tool is particularly helpful. 

RF Filter Design and Innovations

While this paper speaks to the necessity of simulation and analysis tools in the enablement of RF and mmWave designs, there is a world of innovations and developments taking place right now in RF filter and microwave filter designs. 

For RF filters, developing filters capable of multi-passband and various stopband processing capabilities is paramount for the spread and development of many RF and microwave technologies. Additionally, trends such as RF spectral sensing could allow operation of RF designs in under-utilized frequency bands paired with the ability to detect potential interference. Finding the perfect balance of RF components that utilize high performance capacities (highly linear, low line-loss, and low DC power necessity) with a uniquely wide operational bandwidth is extremely challenging even by today's technological standards.  Creating new filter technologies will require a host of simulation and analytical capacities like  lumped-element models, integrated circuit design platforms, or 3D-waveguide simulators. 

For mmWave and Microwave filters, frequency-selective surfaces have enabled much technological development in order to avoid potentially problematic electromagnetic intereference. Multi-layer metasurfaces are being explored to enable higher bandpass resonances, as well as low insertion loss post-wall waveguides to enable easier through-hole fabrication. Part of the difficulty of miniaturization and utilizing particular materials and surfaces is in the actual production and not just the theorization of the device, as such finding ways to continue to ease production of communications technologies expanding into industrial and consumer electronics is paramount.