The technical column "Types and Characteristics of RF (Radio Frequency) Inductors: Selecting the Optimum Components" on the Murata Manufacturing Co., Ltd. product information website explains that RF inductors can be divided into three types by manufacturing method (wire wound, multilayer, and film types).
Among these, the LQW series of wire wound type RF inductors are characterized by a high Q value, low DC resistance, support for large currents, high inductance, and it contributes to improving the performance of various RF circuits.
To enable a more effective selection of components, Murata's LQW series lineup is introduced in terms of these three factors.
2. Lineup of LQW series of wire wound type RF inductors
Generally, as the size increases, the Q value (a value indicating the quality of the coil) increases and a large inductance value can be obtained.
For small sets such as mobile phones and modules, the LQW03/04/15 series tend to be used, taking size into consideration, and for relatively large sets, such as cellular phone base stations and set-top boxes (an electronic device connected to a TV receiver), large components such as the LQW18/2B/2U series tend to be used, with a focus on characteristics.
High Q characteristics are realized due to the thick wire winding technology and core design optimization.
Although the lineup of inductance is limited due to the use of thick wound wire, this is the optimal series for improving RF characteristics and reducing the size of the inductor while maintaining its characteristics.
The differences in Q characteristics are shown in Figure 2.
Inductors are also used in RF circuits for filter and choke applications. When the countermeasure frequency is low, a relatively high inductance value is required to form a filter circuit, but by using a ferrite type inductor, the circuit can be made more compact.
The lineup of ferrite-type LQW series products is shown in Figure 3.
When compared with Figure 1, it can be seen that this series is compact with a high inductance. But because the Q value tends to be lower, it is not suitable for matching applications that require a high Q value.
Check the following references for ferrite-type applications.
・"Inductors suited for the bias tee circuit of automotive cameras [wiring inductor room]"
・"Proposal of the Noise Suppression Technology in the PA and Power Line"
◆Lineup of automotive products
In anticipation of the practical use of automated vehicles in the future, efforts are being made to expand the LQW series of products that conform to the AEC-Q200, which can be used in onboard RF circuit matching and choke coils. Click the “For Automotive” tab in the “Selection tool” section in the lineup list for RF inductors page to check the RF inductor onboard lineup that includes the Murata LQW series.
Murata Manufacturing has released its SimSurfing design tool to aid in the selection of components at the customer's design stage. In addition to searching for the optimal product from the required specs, you can also compare the characteristics of products and download simulation data such as S-parameters and SPICE models.
The LQW series of wire wound type RF inductors is characterized by a high Q value, low DC resistance, support for large currents, and high inductance.
Select the optimal product from the lineup of product series based on the size, high Q value, and ferrite type required by the customer.
Product Engineering Section 3, Product Engineering Department, EMI Filter Division
Murata Manufacturing Co., Ltd.