5 Waveguide Diplexer Applications & Manufacturers

This page covers the basics of Waveguide Diplexers, including application notes and a list of vendors/manufacturers. It also provides a link highlighting the difference between a diplexer and a duplexer.

Modern multimode modems are commonly used in advanced wireless telecom systems, supporting various modes such as GSM, CDMA, and LTE. To use the same antenna for these different technologies, it’s necessary to separate the different frequency bands. This is where a diplexer comes into play.

A diplexer separates wide frequency bands using broadband filters embedded within it. When this diplexer is designed to be compliant with waveguide dimensions, it is known as a waveguide diplexer.

Unlike a diplexer, a duplexer separates frequency bands that are closer together. This requires narrow band filters, which is the major difference between the two RF devices.

Inside a waveguide diplexer, you’ll typically find two bandpass filters and an RF circulator. These devices usually don’t require tuning, making them relatively inexpensive when produced in large quantities.

Figure 1: Waveguide Diplexer from CERNEX, Inc.

CERNEX, Inc. manufactures both waveguide and coaxial diplexers, available in generic communication bands ranging from 0.4 to 110 GHz. These RF devices are widely used in outdoor units and systems, serving as a main component that interfaces the transceiver with the RF antenna.

Here are the general technical specifications of a waveguide diplexer:

• Offers high isolation or rejection (in dB).
• Offers low insertion loss.
• Available in coaxial and waveguide interfaces.
• Pass band of frequency of operation.
• Average power handling capability (in Watt).
• In-band ripple (in dB).

Waveguide Diplexer Manufacturers or Vendors (USA)

The following is a list of manufacturers and vendors of Waveguide Diplexers:

Waveguide Diplexer Applications

Following are five applications of waveguide diplexers beyond the usual uses like amplifiers, antennas, duplexers, mixers, test & measurement, Satcom, radar and microwave systems.

1. 5G & IoT Infrastructure in Ka–Band : They are used in 5G links operating in Ka-Band to separate downlink and uplink signals.
2. Millimeter Wave Astronomy & Remote Sensing : They are used in astronomy receivers to combine multiple local oscillator frequencies to feed heterodyne detectors.
3. E-Band Fixed Wireless Communications (71–86 GHz) : In this band, waveguide diplexers enable high speed and point to point links by isolating narrow transmit/receive bands.
4. Rotary Joint Systems for K/Ka‑Band : allow stable signal transmission in rotating platforms
5. Broadcast & TV Signal Combining : Waveguide diplexers combine video and audio signals in UHF/VHF broadcast transmitter systems.

Conclusion: These specialized applications leverage the frequency selectivity and high isolation of waveguide diplexers to handle multi-band signal routing in 5G, satellite/astronomy, broadcast, and rotating RF platforms, going well beyond conventional uses.