#### Impedance matching of the WPT coil

2016-11-18

Hello, I will explain how I matched input impedance of the WPT coil to 50 Ohm. Please look at the following picture. You can see that SMA cable is directly connected with the feed coil. Let’s see the frequency characteristic properties of this WPT coil. Frequency range is between 1 MHz and 27 MHz. So the center frequency is 14 MHz (=0.5*(1+27) MHz) that is the resonant frequency of this…

#### Measuring Lumped Elements Values for WPT coil

2016-11-16

Hello. I will explain how to measure and  decide  lumped elements values for WPT coil. Here is the WPT coil that I made for my experiments. The WPT coil consists of a resonant coil and a feed coil with SMA connector. The resonant coil is spiral and has parasitic capacitance between the spiral lines and this capacitance make this coil resonate at LC resonant frequency. The feed coil is a…

#### Z parameters of the coupled inductors network

2016-11-04

Circuit theory is very good tool to understand and calculate the WPT system. In order to understand what happens in the magnetic coupling in circuit theory, two port network theory provides us good knowledge. Let’s start discussion with the following figure. The figure shows the schematic of the 2-port network. the 2-port network will be anything such as band pass filter, transmission line or WPT system. We can describe this…

#### Wireless Power Transfer Analysis using LTSpice

2016-11-02

LTSpice can be used to calculate the efficiency and other parameters in wireless power transfer (WPT). First, We build the equivalent circuit diagram of the WPT system below. The figure and data came from the following paper. Sample, A. P., Meyer, D. a., & Smith, J. R. (2011). Analysis, experimental results, and range adaptation of magnetically coupled resonators for wireless power transfer. IEEE Transactions on Industrial Electronics, 58(c), 544–554. http://doi.org/10.1109/TIE.2010.2046002…

#### EM Simulation

2016-10-17

(1) Solver : Femtet   Reference : at non-resonant frequency state

#### LTSpice Tutorial 01

2016-08-12

How to import the transistor spice model into your LTSpice. LTSpice : How to import the transistor spice model from Seong-Hun Choe

#### RF Power Amplifier Tutorial (1)

2016-08-06

RF パワーアンプに関する内容をまとめてみました。   RF Power Amplifier Tutorial (1) from Seong-Hun Choe