Mathematical modeling of microwave channels of a semi-active radar homing head

Abstract

Objectives. Radar homing heads of guided missiles form a large group of radars which differ from other radars due to their specific purpose. The advantages of a semi-active radar homing head (SARH) include the ability to have a powerful irradiator at the command post and, as a result, a powerful reflected signal from the target. This results in an increase in the range of its detection and guidance. The absence of an emitter simplifies the missile’s onboard control equipment, reduces its weight and dimensions, thereby improving its maneuverability and increasing the guidance accuracy, resulting in the greatest distribution of this type of SARH. However, in order to determine the exact Doppler shift of the target signal as part of SARH, a reference signal with a frequency coinciding with the illumination transmitter signal must be supplied to the receiving path. This study aims to synthesize and analyze the SARH receiver circuit with improved accuracy characteristics.Methods. The following methods are used: statistical radio engineering; optimal signal reception theories; and computer modeling in CAD AWR Design Environment.Results. A mathematical model of the SARH receiver was obtained and analyzed. The proposed receiver model allows the spectral characteristics of signals to be calculated at any point of the microwave paths, as well as signal characteristics at the input of the head channel, at the output of the first conversion mixer, at the output of the first intermediate frequency selector, and at the output of the receiving path. The calculated values of the main characteristics of high-frequency channels are also given.Conclusions. The resulting model allows the frequency dependencies of main parameters of the receiving path, such as the gain factor, noise factor, decibel compression points, and third-order intermodulation intercept points to be estimated. The values obtained during the simulation are maximally close to existing systems, since the models of real-life and mass-used microcircuits thu created are used as the main elements when designing high- frequency paths. The model can be used to study methods of improving technical indicators, as well as to develop new principles and schemes for developing radioelectronic complexes, for example, when designing a receiving path using advanced radio photonics.