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RF Switch Maintain The Basic Characteristics Of Square Wave

Sep 27, 2017

Many RF switch manufacturers use two major parametric topologies and bandwidth to describe their products. While these specifications are important in the evaluation phase, they can not provide the buyer with enough information to support decision making.

The switch is a common device in the RF path. As long as it involves the switch, you need to use it. Common RF switches are electronic switches, mechanical switches, and PIN switch. Today, the main talk about electronic switches.

Absorbent switch, in the off state, through the 50ohm load to absorb the reflected signal, so in the off state, the standing wave is also very good.

Reflective switch, in the off state, in an open or short circuit state, the total reflection of the signal, so in the off state, the standing wave is poor.

Typically, the reflective switch to withstand the power than the absorption switch.

In general, reflective and absorptive switches can be used; however, if the indicator performance is more sensitive to the reflected wave, you need to select the absorption switch.

Hot switch: switch with power switch. When used, it is necessary to focus on this power level. Especially for high-power switches, generally require, first turn off the RF signal, and then cut the switch. For example, only the road repaired, the car can open.

Make sure that the input and output terminals of the switch need to be charged. Some switch manual, will be marked, you can not add; single switch manual, the label must be added.

Control the time and frequency response of the RC filter. The time response of the RC filter is required to not exceed the value required by the system. For example, your system to send and receive conversion time is 100us, then your RC filter response time limit can not exceed 100us-switch response time. RC filter bandwidth is not as narrow as possible to control the signal frequency of 3 to 5 times is appropriate, so that can not only filter out most of the harmonic components, but also to maintain the basic characteristics of square wave.

RF and microwave switches can be divided into electromechanical relay switches and solid state switches two categories. These switches can be designed for a variety of different configurations - from single-pole single-throw to single-pole, six-throw, or more-throw configurations that can convert a single input into 16 different output states. The switch is a double pole and double throw configuration switch. This type of switch has four ports and two possible switch states, which allow the load to switch between the two sources.