RF Microtech Develops Complex UWB Filter In Record Time
Another success story for RF Microtech.
A great achievement for the company, whose outcomes in projecting Complex UWB Filter have been published by AWRCORP, but also exalted on the Microwave Journal (see the links below)
The Design Challenge
Expo Milano 2015 was a universal exposition that hosted over five thousand events in six months. The organizers had contracted with several mobile service providers to deploy stations throughout the expo area to provide complete mobile service coverage for the event. In addition, Italian government security services relied on mobile base stations strategically placed throughout the expo to ensure communications for the event, including the public safety network. However, the lobe of one of the mobile service antennas directly interfered with the communication signals of a critical security control base station and the issue had to be resolved immediately as the expo was opening in less than a month. RF Microtech was asked to provide a validated full-wave electromagnetic (EM) simulation of a 2-port ultra-wideband (UWB) filter that could reject all five mobile service bands with greater than 35 dB of rejection. Furthermore, the filter had to ensure 80 MHz to 6 GHz wide-band transmission with insertion losses less than 2 dB RF Microtech’s client, H3G, also required that the device fit within a 1x1x0.2 meter enclosure, while still providing acceptable levels of coexistence to 6 GHz without signal degradation. The validated EM simulation had to be delivered within two weeks and the complete deployable device by the time the expo opened.
“We chose Microwave Office because it could easily and quickly optimize the cascade of a series of full-wave component blocks of a very large and complex UWB filter structure. Using Microwave Office, we were able to reduce optimization and development time by 90 percent, a critical factor in delivering this project in a very short timeframe.”stated Roberto Sorrentino Honorary President of RF Microtech
The RF Microtech design team immediately went to work developing a circuit model of five independent notched-band filters (NBFs) cascaded along a transmission line.
The team chose NI AWR Design Environment, specifically Microwave Office circuit design software, for this time-critical project. Each independent filter was designed as a 4th or 5th order NBF, composed of several cascaded stages of N shunt resonators. The individual filter specifications required that the filter resonators’ high unloaded Qs be > 1000, with the additional challenge of having no spurious modes under 6 GHz. Each of the transmission line and filter sections were then implemented in ANSYS HFSS full-wave electromagnetic (EM) analysis tool. The S11 and S21 results corresponded well with the initial circuit simulation.