Solid-State RF Switching to 8GHz
Pickering Interfaces manufactures a proprietary range of solid-state RF products with frequency cover to 8GHz. The range includes both RF switches and digital step attenuators. The RF switches used are based on CMOS technology and integrated on Pickering Interfaces designed PCB materials with RF-controlled characteristics. The modules can be used in any PXI chassis or Pickering Interfaces proprietary modular LXI chassis 60-102 and 60-103.
What are solid-state RF switches?
They are switches fabricated from either CMOS or gallium Arsenide FET's. Pickering Interfaces uses CMOS switches.
What advantages do solid-state switches have?
These switches have very fast operating times compared to mechanical switches and have a very long service life. EMR switches become more challenging to fabricate as the frequencies rise and even minor variations in mechanical dimensions adversely affect their performance. As frequencies extend beyond 3GHz, EMR switches become more expensive, and edge line mechanical switches (such as those manufactured by Radiall) are used. Their lifetime (the number of switch operations they will endure under light load conditions) also becomes more limited.
Our solid-state RF switches also automatically terminate unused input signals in 50Ohms to reduce VSWR issues in the connection system - a feature that adds considerable extra cost on mechanical switches.
These designs also feature very high isolation compared to EMR solutions but not as high as edge line mechanical relays.
What disadvantages do they have?
These switches cannot handle as much RF power as their mechanical counterparts, and they do not handle DC signals very well. At lower frequencies (typically around 1MHz to 10MHz), the manufacturers de-rate their specification. To avoid potential damage to the switches by accidental application of DC signals (for example, from amplifiers), we AC couple our switches to preserve a useful bottom frequency down to a few MHz.As the RF switches are fabricated from semiconductors, they can exhibit some non-linearity; the 40-880 series has a typical third-order intercept level greater than +60dBm.
Where do Pickering Interfaces recommend these switches are used?
They are particularly relevant for applications requiring signal levels up to +20dBm - more than enough for most applications. At +20dBm IP3 products are typically less than 80dBc. The switches can be used at higher powers, but users need to assess if performance aspects like intermodulation might be an issue.
What solid state switches does Pickering Interfaces offer
We offer a range of solid-state switches based on commercially available switches integrated into our switch designs using controlled RF materials and proprietary SMA connectors. These designs provide excellent performance beyond 8GHz. The range includes a programmable attenuator.
40-880 SPDT Switch
Dual, Quad, Hex or Octal SPDT Switch Automatic termination of unused output ports 10MHz to 8GHz frequency range
40-881 SP6T Switch
Single or Dual SP6T switch Automatic terminations of unused ports 10MHz to 8GHz frequency range
40-882 SP4T Switch
Dual, Triple or Quad SP4T switch Automatic termination of unused ports 10MHz to 8GHz frequency range
41-182 Programmable Attenuator
Three channels per module Level control to 0.25dB 10MHz to 6GHz frequency range
40-884 4x4 Matrix
A 4x4 8GHz matrix in a compact PXI format