Switches, Relays & Keypads


Matrix switches: blocking vs non-blocking

11 July 2007 Switches, Relays & Keypads

In the RF and wireless industries, system performance requirements seem to expand almost daily. These systems continue to encompass more and more of today's broad-reaching technologies.

Engineers working in this environment are often tasked with designs that must combine and distribute RF signals from multiple input devices, while at the same time making those signals available via multiple outputs. In many cases, an RF Matrix Switch can be the solution to this problem. This article explores the three most basic types of Matrix Switches, and will touch upon the inherent advantages and disadvantages of each.

Blocking Matrix

A Blocking Matrix Switch is built with switches on both the inputs and the outputs. Therefore, each input signal can be switched to one individual output port. If an application requires an input to be available to more than one output simultaneously, then a Non-Blocking Matrix becomes necessary. Figure 1 illustrates the connectivity of a 3 x 3 Blocking Matrix Switch and Figure 2 depicts some of the possible connection states with this type of switch.

The two most notable advantages of a Blocking Matrix Switch are insertion loss and isolation. Because the design uses only switches and no power dividers, the insertion loss will be relatively low. Using only switches also makes it possible to maintain very high isolation from input to output. However, one significant disadvantage to this type of design is its cost. RF switches are generally more expensive to produce than RF power dividers.

Figure 1. 3 x 3 Blocking Matrix Switch
Figure 1. 3 x 3 Blocking Matrix Switch

Figure 2. Possible connection states
Figure 2. Possible connection states

Non-Blocking Matrix

A typical Non-Blocking Matrix Switch is one that is built with power dividers on the inputs and switches on the outputs. Each input signal is thereby split to all output switches. This means that, in a 4 x 20 Non-Blocking Matrix Switch for example, the four input signals could be split to all 20 outputs. This would allow an engineer to select the signal to be seen on each output. Or, a user could even have a single input connected to all 20 outputs without even using the other inputs. Figure 3 shows the layout of a typical 3 x 3 Non-Blocking Matrix. Figure 4 depicts some of the possible connection states with this type of switch.

Figure 3. 3 x 3 Non-Blocking Matrix Switch
Figure 3. 3 x 3 Non-Blocking Matrix Switch

Figure 4. Possible connection states
Figure 4. Possible connection states

The obvious upside to a Non-Blocking Matrix Switch is its greater switching flexibility. However, certain compromises have to be made in order to achieve that increased flexibility. Because it uses power dividers, a matrix like this will have switched to receive the same input signal, the isolation between output ports is determined by the isolation of the power divider. Typically this will be about 20 dB.

Non-Blocking Matrix - Extended Variation

An Extended Variation Non-blocking Matrix Switch is one that is built with power dividers on the inputs and on the outputs. Depending on the functionality needed, an array of either 1P1T switches or programmable attenuators is placed between the layers of power dividers. This configuration allows for multiple input signals to be available at one output. When the programmable attenuator option is exercised, a user may individually adjust the strength of each signal being received by an output. See Figure 5 for a 3 x 3 Extended Variation Non-Blocking Matrix. Figure 6 shows some of the connection states and manipulations that are possible with this type of switch.

Figure 5. 3 x 3 Extended Variation Non-Blocking Matrix Switch
Figure 5. 3 x 3 Extended Variation Non-Blocking Matrix Switch

Figure 6. Possible connection states
Figure 6. Possible connection states

This configuration offers even greater switching flexibility than a standard Non-Blocking Matrix Switch and can even be used bi-directionally. Once again however, this configuration does have its disadvantages; using twice the number of power dividers results in an even greater nominal insertion loss through the system.

When choosing the right Matrix Switch design, it is important to have a thorough understanding of the application. Many different variables must also be taken into account, along with the matters of connectivity that were addressed in this article. Everything from RF performance and reliability to control interfaces and programming should be considered before making a decision.





Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Versatile micro switches
30 June 2020, TRX Electronics , Switches, Relays & Keypads
The V19, Honeywell’s unsealed micro switch family, provides a cost-conscious switch solution to assist in hitting overall system-level cost and design goals in high-volume applications. Suitable applications ...

Read more...
Tactile switches for demanding applications
29 April 2020, Brabek , Interconnection, Switches, Relays & Keypads
The Multimec switch from APEM has been designed with the intention to manufacture the best possible switch. The company’s automatic production lines have 100% in-line testing, but before the parts get ...

Read more...
Waveguide electromechanical relay switches
26 February 2020, RF Design , Switches, Relays & Keypads
Pasternack has just launched a new series of double ridge waveguide electromechanical relay switches which perform over broader frequency bands, making them ideal for applications involved with electronic ...

Read more...
Illuminated pushbutton switches
25 November 2019, TRX Electronics , Switches, Relays & Keypads
The KLS series expands C&K Switches’ product offering in the LED pushbutton family. It meets the market requirements for haptics and sound with clear ‘click’ feedback. With various cap options and bright ...

Read more...
Connectors for automotive electronics
31 July 2019, TRX Electronics , Switches, Relays & Keypads
TE Connectivity’s HDSCS connector series is designed to meet the rigorous demands of the commercial vehicle industry and off-road applications that require high standards of performance. Made from a rugged ...

Read more...
SP4T switch matrix
26 June 2019, Conical Technologies , Switches, Relays & Keypads
Mini-Circuits announced the release of the latest addition to its test system lineup, the RC-2SP4T-40 USB and Ethernet controlled single-pole four-throw switching matrix. This new device is fitted with ...

Read more...
Wi-Fi microcontroller
29 May 2019, iCorp Technologies , DSP, Micros & Memory, Switches, Relays & Keypads
The ESP32-S2 from Espressif Systems is a highly integrated, low-power, 2,4 GHz Wi-Fi microcontroller SoC (system-on-chip) supporting Wi-Fi HT40 and 43 general-purpose I/Os. Based on an Xtensa single-core ...

Read more...
Miniature slide switches
29 May 2019, Wiltron Agencies , Switches, Relays & Keypads
Hartmann Codier’s new SR254 product range of slide switches provides variants in horizontal and vertical versions that can be used as on, off, or change-over switches with contact wiping on make and break. ...

Read more...
DIN-rail mounted SSRs
30 April 2019, TRX Electronics , Switches, Relays & Keypads
Crydom’s SeriesOne DIN-rail mounted AC and DC output solid state relays (SSRs) offer a cost-effective combination of size and ratings thanks to their patent-pending design. The product line includes single-channel ...

Read more...
Dual-circuit tact switch
27 March 2019, TRX Electronics , Switches, Relays & Keypads
C&K has extended its KSC range of tactile switches with the addition of a new dual-circuit model. The new KSC-DCT tact switches offer single-pole double-throw, normally-closed normally-open dual-circuit ...

Read more...