Diplexer: Advantages and Disadvantages

This page covers the advantages and disadvantages of a Diplexer. It mentions the benefits and drawbacks of RF Diplexers and describes RF Diplexer basics.

What is an RF Diplexer?

Introduction: A diplexer is an RF device that separates two wide bands in the receive direction and combines them in the transmit direction. For an RF diplexer to work satisfactorily, the frequency bands it operates on should be wide apart. It typically uses one Low-Pass Filter (LPF) and one High-Pass Filter (HPF), or two Band-Pass Filters (BPFs) inside to separate the bands.

Image alt: RF diplexer

Example application #1: Transmission of VHF and UHF frequencies using a single antenna

Two widely separated bands used for different applications can be combined and transmitted over the same antenna. The diplexer separates out the two different bands in the receive direction.

For example, two frequencies used for different departments, such as police and fire, can be combined and transmitted using the same single radio tower located in the city with the help of an RF diplexer.

Example application #2: Sharing of a single antenna between a transmitter and a receiver

Benefits or Advantages of a Diplexer

Following are the benefits or advantages of using a Diplexer:

• The same antenna is used for transmitter and receiver chains, which helps in minimizing the cost of the entire system.
• It simplifies the design of the end product due to less space requirements for the antenna structure.

Drawbacks or Disadvantages of a Diplexer

Following are the disadvantages of using a Diplexer:

• The resultant noise figure increases due to the insertion loss of the diplexer.

• As an RF diplexer is similar to an RF duplexer device, refer to the advantages and disadvantages of an RF duplexer to understand the merits and demerits of both.

• Also, refer to the advantages and disadvantages of an RF circulator.