High Frequency Design
Introduction

Radio frequency, any frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. Many wireless technologies are based on RF field propagation.

High frequency (HF) radio frequencies are between 3 and 30 MHz. It is also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred meters). Frequencies immediately below HF are denoted Medium-frequency (MF) -- 300 kHz - 3 MHz, and the next higher frequencies are known as Very high frequency (VHF) -- 30 MHz - 300 MHz.

Short wavelengths are associated with high frequencies because there is an inverse relationship between frequency and wavelength. Shortwave radio operates between the frequencies of 3 MHz and 30 MHz and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than the long wave lengths widely in use at that time.

High Frequency Filter Design Considerations

MOSFET High Frequency Model