Everything You Should Know About Return Loss Measurements Using a Directional Coupler

Everything You Should Know About Return Loss Measurements Using a Directional Coupler Contents 1. Introduction 2. Theory 3. Measuring reflection with a directional coupler 4. Applications 5. Conclusions 1. Introduction Return loss is an important parameters of any RF (Radio Frequency) device. It is a measure of the amount of power reflected at a port. From it, impedance levels can be calculated and amplitude variations in transmission lines predicted. For one port devices, it is the only existing scattering parameter too! Usually, return loss is measured using a directional coupl [...]  Read more >

Power Splitters, Combiners, Couplers and Hybrids: A Taxonomy

Power Splitters, Combiners, Couplers and Hybrids: A Taxonomy The landscape of power splitters, combiners, couplers and hybrides can be daunting at first glance. However, when we classify these devices according to their functions and take the different kinds of operating principles into account, the pictures becomes clear. To assist the RF engineer in choosing the right device for the job, we constructed a taxonomy of these devices. 1. Some Constraints to Consider First In this article, we choose to look at all devices as three-port models. Because, in most cases, [...]  Read more >

Modeling Devices with S-parameters

Modeling Devices with S-parameters Scattering parameters or S-parameters for short, are the standard way to describe the behaviour of all kind of RF devices. Both passive and active. So, what are these parameters and why are they so popular? In order to fully grasp the full potential of S -parameters, it is useful to lay down some basic concepts first. (Note: some understanding of transmission line theory is helpful when reading this article) 1. Concepts The basic idea behind S-parameters is to look at a device (or more generally, a netwo [...]  Read more >

When Should I use a DC Block in RF Applications?

When Should I use a DC Block in RF Applications? Sometimes it is necessary to block the DC component in a RF signal. There are two main reasons to do so. The first one is to protect equipment or components that can't handle DC signals without damaging them. The second reason is to improve measurement accuracy. 1. Function of DC-blocks in RF applications 1.1 Protection The most obvious function of a DC-block is to protect components that can't stand DC voltages. For example, a mixer that uses a transformer at its input, as many do! If such a component i [...]  Read more >

Universal Aluminium Enclosure for RF Circuits

Universal Aluminium Enclosure for RF Circuits Every RF engineer faces the challenge of getting the PCB into an enclosure without compromising RF performance. An enclosure that lets you easily switch PCBs not only makes life easier, but significantly improves the prototyping process. That is, in a nutshell, what the Gquipment RF-MINI-Enclosure was designed for. Enclosure Design Parameters To achieve our goals with the RF MINI, several key design decisions had to be made: Dimensions- The dimensions of the enclosure were chosen in order to support a PC [...]  Read more >
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