L-Band, S-Band, and X-Band Frequencies


L-Band, S-Band, and X-Band Frequencies

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Alumina AL-300, AL-500, AD-94, Beryllium Oxide, Quartz and more

We have a number of products being sold around the world in L-Band, S-Band, and X-Band frequencies. We can quickly and routinely make a custom design to meet your specific needs and we can also turnkey your RF Window design to your exact specifications.

In the mid-’90s, Altair introduced its first-ever proprietary S-Band RF Window designed for medical oncology accelerators. Today we sell thousands of these RF Windows and have leveraged this original design into many new RF Windows for various applications in volume.

Furthermore, we supply both custom and production RF Windows used by OEM's and various research entities. Our Windows are used on many types of RF devices but are primarily used on linear accelerators for medical (oncology), industrial screening and national laboratory applications.

RF Windows transmit RF or microwave power from a vacuum into an air-filled or more likely an inert gas-filled transmission line like a waveguide. It is a resonant cavity designed to maximize RF (radio frequency) power transmission, with minimal loss over the desired frequency range.

Operating Frequency (GHz) Band Maximum Average Power (kW)* Maximum Peak Power (MW) Maximum VSWR Maximum Insertion Loss (dB) Max Pressure (psig) Wave-guide
1.30 L 75 20 1.10 0.1 30 WR650
2.856/ 2.998 S 36 20 1.10 0.1 30 WR284
2.998 S 10 20 1.15 0.1 30 WR284
9.30 X/H 2 2 1.10 0.1 30 WR112

Windows are impedance matched to minimize reflection and achieve low insertion loss and excellent VSWR. *Operating RF Window assemblies at maximum average power conditions may require liquid cooling. Altair Engineering can provide thermal simulation services if needed.

Looking to get it right the first time?

RF window, S-Band manufactured by Altair Technologies Inc.

Who will
to your exact

Frequency ranges can be shifted to meet your requirements.

Do you need a custom RF Window assembly? No problem, our technical team can provide elecromagnetic and mechanical simulations to design an assembly that meets your performance specifications.

RF Window flanges are typically made out of stainless steel and we supply
virtually every flange type including conflats, SLAC or Varian type flanges, LIL, Cover, Choke & Vacuum. We can also configure your Window to have a mating Weld flange of almost any configuration.

• Peak power ratings with pressurized dry air (@30lb/in2-g)
• Peak power ratings are subject to the pulse length.
• Windows are typically coated with a multipactor coating.
• Windows bakeable to >500 °C

Frequently Asked Questions

How are RF-Windows used in a radiotherapy LINAC (Linear Accelerator)?

RF windows are a transitioning device that allows RF power (radiofrequency power or microwave power) to pass through freely but block any and all gas transfer. The “window” itself is most commonly made of high grade ceramic and is housed in a length of waveguide. One side of the ceramic faces the vacuum of the linac. The other side faces the pressurized waveguide that leads to the RF power source (magnetron, klystron, …). This allows the linac to be connected to the RF power source without those two devices having to share vacuum space. RF power can travel through vacuum and gas while the linac and magnetron only function in high vacuum. RF windows make this arrangement possible and provide infinite packaging options for the linac and magnetron combo. In a Radiotherapy Linac, these packaging options make the overall machine, and therefore the entire radiotherapy suite, smaller and considerably less expensive for the hospital. Additionally, separating the linac and magnetron makes servicing both of them significantly easier.