Design Of Microwave Oscillator Based On The Composite Right/Left-Handed Transmission Line

The signal generating circuit is essential in the microwave RF system of communications, navigation and radar field where the oscillator is the very core device. The requirements of the oscillator performance also grow more and more with the rapid development of microwave and communication technology. The trend of oscillator development is small size, less cost, low noise, high stability and reliability.The oscillator is a device which can be used to generate electronic signals. The basic parts of the oscillator circuits include the transistor controlling the energy, the feedback network and the frequency selective network which is mainly used to select the required oscillation frequency.The left-handed material is one kind of metamaterials with unique electromagnetic properties, which is a new hot research spot in microwave electromagnetic field. It has attracted more and more attention and research because of its good application prospects. There are two methods to implement left-handed material currently, which is the improved or derived structure based on Smith model and the model based on composite right/left handed transmission line (CRLH TL).The paper demonstrates a design of microwave oscillator working at 1.85GHz based on CRLH TL. The oscillator at 1.85GHz can be applied in DCS 1800 communication. The frequency selective network of the oscillator is composed of zero order resonator based on CRLH TL coupled with microstrip line, which has the characteristics of left-handed materials. The proposed oscillator can meet the high requirement of small size, low cost, high stability and harmonic suppression in practical application.