The Design Of An L Band Transmitter

With the rapid development of wireless communication, the transmitter is widely used in all aspects of social life.Transmitter is in order to change medium frequency signal into the radio frequency signal and emit the signal with desire power. As a part of the transmitter wireless communication, the transmitter plays a pivotal role in the wireless communication system. Transmitter sometimes is the key to determine the performance of a communication system. The L-bands is the key of frequency bands in wireless communications, such as satellite communications, radio, radar and so work in L-bands.Therefore, it is very meaningful that to research the RF front-end modules of transmitter.This paper based on the actual project requirements, discussed the research and design of the L-band RF transmitters, and developed a high-target, high stability L-band transmitters. The transmitter has two mixer module and an amplifier module. The purpose of the first mixing module is let the IF1 signal input to the first mixer module and get the RF1 signal which has higher frequency than input frequency.The second mixer module is the same as the first mixer module. It will change the input IF2 signal to the RF2 signal. The final amplifier module contains two amplifiers, two filters and so,The purpose of the module is to increase the power of the signal. In addition, the transmitter has a module to convert the supply voltage and has current and power comparators to ensure that the system work normally.In the process of design L-band transmitter, we used ADS simulation software to simulate microwave circuit and applied PCB designing software to design the bias voltage for the microwave circuit.Otherwise, we apply the spectrometer, vector network analyzer and other instruments to test the transmitter.In addition, we discusses the design of the filter which is the key component of RF front-end in this paperIn this paper, firstly we introduce the related research background and basic theory of L-band transmitter, and then discusse how to design and test the filter which is the key component of RF front-end.Finally, we describe how to distribute the index of the L-band transmitters and the design problems encountered in the process of develop each module circuit in detail.