Study of a solid-state transmitting device with a phase correction system, which increases the summing efficiency

Abstract

Modern radar is a complex system, built on the basis of almost all the achievements of such areas as radio electronics, computer engineering and, of course, microwave devices. One of the most important units of radar, which determines the potential characteristics of the system as a whole, is the transmitting device. Nowadays the task of signal transmission with minimal losses in transmission lines and obtaining required power levels at the output of the transmitting device is relevant. However, existing methods may be insufficient to accomplish this task. In this regard, it may be necessary to improve or develop new systems and methods using the latest advances in microwave and antenna technology, radio and microelectronics, the totality of which will provide devices with these parameters. One such way to increase the stacking efficiency and output power of the transmitting device is to correct the phase of the amplification channels of the transmitting device in the range of operating frequencies. In this article the advantages of using solid-state transmitting devices in radar stations over electric-vacuum amplifying devices are considered. The most common ways of summation the power of microwave devices are described. An algorithm of the phase correction system is presented. The results of an experimental study of the system of gain channel phase correction for a transmitting device with eight gain channels, operating in a relatively wide frequency range, are presented. The proposed amplification channel phase correction system compensates the existing difference in the electrical lengths of the elements of the divider-adder path and amplifying modules in accordance with the algorithm, by means of controlled phase shifters (integrated into each amplifying module). The change in the phases of the microwave signal in (n-1) amplification channels is performed based on the calculated phase corrections obtained on the basis of successive estimates of the total output power of the reference amplifying module with each of the (n - 1) modules, where n is the total number of amplifying modules (channels amplification) in the transmitter. The output power is estimated by the ADC according to the level of the microwave power envelope at the lower, middle and upper frequencies of the operating range, taken from the adder output by a directional coupler. The performance of the phase correction algorithm is ensured by the control device of the amplifying module, the control and monitoring device of the transmitting device, the automatic monitoring and control system from the processing and indication system, as well as the appropriate interface at the operator's workplace. The proposed algorithm corrects the phases of the amplification channels according to the values obtained by the calculation method based on the data measured in the process of phase correction, which made it possible to reduce the maximum required number of phase shifter adjustments to 3 for each of n and each frequency, thereby ensuring a threefold increase in device performance. It was experimentally confirmed that the application of the proposed technical solution increases the efficiency of power summation of the considered transmitter from 70% to 94% - 99% (excluding active losses in the divider-adder and RMSD of the output powers of the amplifying modules) and an increase in the output power of the transmitter by 30% was achieved. The obtained results can be used to improve the algorithmic-software support of developed or modernized transmitting devices of radar stations.