RF microwave filter manufacturer – A brief comparison of the different RF/ MW filters and their manufacturing costs.
If you have been looking for RF microwave filter manufacturers, you would probably have noticed that most RF and microwave manufacturers produce some of the following types of filters:
LC filters – These are also known as lumped element or discrete filters and are constructed using inductors and capacitors. LC filters are used in the lower frequency bands such as HF–band to L-Band. But higher frequency LC filters up to 6GHz are also available. The main advantage of an LC filter is the size and the relative low cost of manufacturing.
Cavity filter – Cavity filters are usually used at higher frequencies from UHF to Ku Band, where it is not practical or possible to employ inductors or capacitors. Cavity filters are machined from metal block and tend to have excellent Q, lower insertion loss and sharp rejection. In terms of manufacturing costs, cavity filters are the most expensive since each filter is manually tuned and require the use of extensive human labor. However, cavity filters have the best performance in terms of losses and rejection as compared to the other type of filters.
Waveguide filter – Waveguide filters are filters that are formed from waveguide structure. They are commonly used in satellite communications equipment such as VSAT, earth ground station receivers and microwave radio. Waveguide filters tend to be used at much higher frequencies than cavity filters and are comparable to cavity filters in terms of manufacturing costs and performance.
Ceramic filter – ceramic filters are made from dielectric resonator and are used as filters in the UHF-band to C-band frequencies. They are also easy to manufacture in large volumes. Hence it is not surprised to find ceramic filters being used in many commercial systems like GSM, GPS and LTE equipment.
SAW filter – SAW filter are also known as surface acoustic filters and are characterized by very sharp rejection and narrow bandwidth. SAW filters are grouped into 2 major groups, IF SAW filter and RF SAW filter. IF SAW filters tend to have insertion loss in passband of between 10 to 30dB and usually require the use of external inductors and capacitors for matching. RF SAW filter on the other hand have insertion loss in the range of a few dBs. SAW filter technology is also a type of filter that can be manufactured in large quantity. Due to their miniature size, their most common applications are in the mobile phones.
There are many RF microwave filters manufacturer globally and it is not common to find an RF microwave filter manufacturer that is able to supply all the different types of filters. RF filter manufacturers tend to focus on producing one or two types of filter, like ceramic filter or SAW filter.
In conclusion, SAW filter and ceramic filters are well suited for high volume manufacturing. Cavity filters and waveguide filters have the best performance but are not manufactured in high quantities like SAW filter and tend to the most expensive amongst all the different types of filters. LC filters are somewhat in between, but they are limited in frequency range because parasitics of inductors and capacitors dominate at higher frequencies. This limits the useful range of these filters to frequencies below the self-resonant frequency of the lump elements.