Remotely tunable
rejection filter for C-band deployment
near Satellite stations

JUN 3, 2021

More than half-dozen companies have collectively spent over $80 billion USD for C-band licenses, a new set of spectra that promise to enhance 5G across USA. A substantial amount that only accentuates the importance for future development. The C band frequency range encompasses 3.7 GHz to 3.98 GHz and is located immediately above the CBRS band, 3.55-3.7 GHz, which could be used for 4G but ideally suited for 5G. Commonly known as “C Band", this frequency band has been used for satellite TV since the 1970’s, today it is used for the satellite downlink for broadcast TV distribution.

C band frequencies have quickly become the most popular 5G band in the world. C band is divided in three bands, by International Telecommunication Union (ITU); band n77, band n78 and band n79.

C band is expected to have cell-coverage of about half-a-mile from each tower, which allows operators to provide solid 5G using existing cell sites.

The C band frequencies will become available to operators in two phases. By end of 2021 the first 100 MHz will likely become available in 46 major markets across the US, covering about 60% of the US population. The other 180 MHz are expected to be cleared by the end of 2023.

Phase 1, C Band deployment, will allow operators to utilize the A block of C Band, 3700-3800MHz. During this phase it will be required to not create any harmful interference towards satellite earth stations still operating in the 3820-3980MHz spectrum. Once the portion of C Band from 3800-3980MHz is made available at the end of 2023, operators will be allowed to utilize the full spectrum from 3700-3980MHz.

C band at 8T8R Cell sites deployment, that are in close proximity (0.5 miles/800 meters) to existing satellite earth stations, will require interference mitigation/rejection filters.

The KA-6008 from Kaelus, is a remotely tunable filter, specifically developed to deliver one solution for both phases.

The unique feature of this interference mitigation filter is the passband tunability. For operators utilizing A1/A2/A3 blocks, the Kaelus KA-6008 allows installation to support Phase 1, 3700 – 3760MHz. Subsequently, simply using a standard AISG command, remotely reconfigure the KA-6008 filter to pass the entire C Band to support Phase 2, 3700 – 3980MHz.

The ability to remotely retune the filter will eliminate the need and costs, associated to access the filter for removal or retuning, i.e., no tower access or climb is required.