![]() Its range can be expanded somewhat by switching in additional inductors. The T configuration in Figure 1a works well but has a limited range of load (R L) matching from 50 Ω to about 5 to 200 Ω. Figure 1 shows several popular configurations. This is an LC circuit usually consisting of a fixed inductor and one or more variable capacitors. This problem is easily solved by inserting an antenna tuner between the transmitter and antenna. Poor Z matching results in weak signal reception. The reciprocal problem exists with a receiver. In fact, the high SWR may actually damage the transmitter output stage. The impact of poor impedance matching on a transmitter is a high standing wave ratio (SWR) that will result in lost power (wasted in the transmission line). That antenna impedance varies widely with the type of antenna, its installation environment, and the frequency of operation. To get the most power to the antenna, the antenna should have a 50-Ω impedance. Most radios-commercial, military, amateur, or whatever-are designed with a 50-Ω output impedance. The first time I encountered a Z-match problem was when connecting my ham radio gear to an antenna. Applications are More Common than You Think Here’s a primer on this topic for your elucidation and cogitation. If you own a recent smartphone, you’re probably using an auto Z-match antenna tuner. Better still is a variable and automatic Z-match circuit that adjusts itself to the immediate load or frequency conditions.Īuto Z matching is more common than you think. For these applications, a variable matching network that you can adjust is needed. But in other applications, that final load may change, or the frequency of operation will change, meaning that a fixed Z-match circuit will not produce the desired results. Some loads are constant thus, a single fixed Z-matching circuit can be used. ![]() Impedance matching to an antenna in a receiver or transmitter is an essential process. ![]() And in power amplifiers (PAs), impedance matching is critical to getting the maximum power to the final load and maintaining PA linearity. ![]() Impedances must be matched to transfer the maximum amount of signal power between stages. Regardless of what you’re designing, getting as much power to a load is a top target. Impedance (Z) matching is an essential part of most RF circuit design. Impedance matching and design considerations.Members can download this article in PDF format. This article is part of the Analog Series: Back to Basics: Impedance Matching ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |