RF Channel Circuit Design And Implementation Of Portable Single Port Vna

Network analyzer is a kind of RF Microwave equipment of great significance,that is widely used in measuring and testing of RF Microwave components and devices. Amplitude, phase and group delay of the component can be measured by VNA, and port impedance in Smith chart can be shown. Using its function of time domain, the distance between measured port to impedance mismatching or circuit mis-function can be shown as well. It’s mainly used for measuring characteristic information like amplitude frequency, phase frequency and group delay of bidirectional S-parameter of network scattering parameter.It is composed with driving source,channel separation component,receiver for detecting signal and display for observing result and processing circuit.With more and more wireless application,the requirement for conditions of environment of VNA becomes much more complicated. During installation and maintenance of BTS cable and antenna system, or radio and radar cable system, or broadcasting and wireless link system, the technicians can easily use the portable single-port VNA to commission effectively, evaluate and discover the system problem and to solve it by avoiding high repairing cost thereafter. This VNA can quickly help with installation and maintenance of any kind of communication systems including cellular network infrastructure, bi-directional wireless communication system under harsh environment. The portable single-port VNA is featured with compact size, lightness and adaptable under kinds of test environment as well as weather condition.As to the questions mentioned above,based on analysis of operation and design principles of single-port VNA, using Altinum Designer, the design of RF circuit diagram and PCB of single-port VNA is finished and actualized on a frequency band of 25 Mhz to 4GHz RF circuit of single-port VNA. The main contents are,1. Analyze the basic configuration and operation principle of single-port VNA in order to know the main circuits composed of RF channel of network analyzer and make sure the design and its function of this part circuit.2. Analyze the structure and working principle of RF directional coupler and carry through the circuit design at 25MHz-4GHz operating frequency, 15 dB coupling, 25 dB isolation, maximum 1.5dB through loss and maximum 1.5 VSWR of the RF directional coupler, and test performance and parameters of it.3. Analyze the structure and working principle of the sampler and complete the circuit design at 25MHz-4GHz RF operating frequency, 25-50 MHz LO frequency and 200 KHz IF receiving frequency of the sampler, also test the conversion loss, flatness of conversion loss and harmonic rejection of the sampler.4. Design for the cascading connection of RF directional coupler and sampler in order to get the RF reference signal and RF reflecting signal needed. And finally fulfill the design of RF channel circuit of the whole single-port VNA. And, test the RF channel circuit, measure VSWR of RF port, level amplitude of port output signal, then finally the IF output, level amplitude and amplitude flatness of reference channel and reflective channel of RF circuit.