DUPLEXERS

A duplexer is an electronic device that allows simultaneous transmission and reception of radio signals through a single antenna without interference. It separates the transmit (TX) and receive (RX) paths using filters.

Duplexers are widely used in:

• Two-way radios

• Cellular base stations

• Repeaters

• Radar systems

• Wireless communication systems

They are essential in systems that share a single antenna for both transmitting and receiving.

A duplexer uses filters (bandpass, bandstop, or notch filters) to route high-power transmit signals to the antenna while isolating and protecting the sensitive receive circuitry from that high power. It ensures both paths don’t interfere with each other.

• A duplexer separates signals that are close in frequency but traveling in opposite directions (TX and RX).

• A diplexer combines or splits signals of different frequency bands (e.g., combining VHF and UHF onto one antenna).

No. Duplexers are tuned to specific frequency ranges and spacing. Using one outside of its design range can result in poor performance or equipment damage.

Frequency separation is the minimum difference between the transmit and receive frequencies that the duplexer can effectively isolate. Typical values range from a few MHz in commercial radios to hundreds of MHz in cellular systems.

Isolation prevents the high-power transmit signal from leaking into the receive path, which could cause receiver desensitization, interference, or even damage to sensitive components.

Common types include:

• Cavity duplexers (used in VHF/UHF repeaters)

• Ceramic duplexers (used in mobile and small devices)

• LC duplexers (based on inductors and capacitors for smaller systems)
• Low PIM duplexers

Tuning a duplexer requires specialized equipment like a spectrum analyzer and tracking generator. You adjust the filters for:

• Minimum insertion loss on TX and RX paths

• Maximum isolation between them

It’s typically done by RF professionals.

Symptoms include:

• Weak transmission or reception

• Overheating of radio equipment

• Interference

• Poor signal quality

Improper tuning or damage can lead to these issues, often requiring recalibration or replacement.

Insertion loss is the amount of signal power lost as the signal passes through the duplexer’s filters. Lower insertion loss means better performance, as more of the original signal reaches the antenna or receiver. High-quality duplexers are designed to minimize this loss.

Power handling depends on the duplexer’s design and materials.
Cavity duplexers often support higher power levels (e.g., tens to hundreds of watts), while ceramic duplexers are designed for lower-power applications such as mobile devices. Always verify the duplexer’s rated transmit power to prevent overheating or damage.

A circulator routes RF energy in a single direction between ports (e.g., port 1 ➜ port 2 ➜ port 3).
An isolator is a circulator with one port terminated, protecting equipment from reflected signals.
A duplexer, on the other hand, separates transmit and receive signals based on frequency, allowing shared-antenna operation.

Most duplexers are passive devices and require minimal maintenance. However, cavity duplexers may need periodic retuning due to temperature changes, vibration, or component aging. Regular inspection ensures stable performance in mission-critical systems.

Yes, we offer custom duplexers tailored to exact frequency bands, power levels, form factors, isolation requirements, or environmental specs. Custom designs are common in aerospace, defense, and high-performance telecom applications.

MCV duplexers are built for high-performance and low insertion loss, with excellent isolation and compact form factors. Available in ceramic and waveguide configurations, they are optimized for demanding environments in telecom, defense, and aerospace sectors.

To place an order for duplexers please contact us and we will help you!