Persons

In designing the receiving-transmitting active phased antenna array (APAA) an important problem is an achievement of the level of maximum outcome between the receiving and transmitting channels. In the work, the concept of building multi-beam receiving-transmitting antenna systems based on APAA has been considered. The criteria for selecting the type of emitter for an S-band antenna with the specified parameters have been presented. It has been shown that the use of a turnstile emitter based on the printing technology can reduce the complexity of manufacturing without compromising the technical parameters. In accordance with the requirements for volume of the tasks of APAA being designed the optimal geometric and electric characteristics of the turnstile radiator have been calculated. In designing the radiating apertures of the multielement APAA the specifics of the dependence of their electric characteristics on the inter-element distance has been taken into consideration. To increase the circular polarization coefficient of the apertures being designed, the method of tearing apart of the radiator with further compensation of the obtained phase using the phase rotators APAA has been implemented. The estimates of the energy characteristics of the multi-element antennas with a given scanning sector for various inter-element distances have been given. To ensure the separation of the receiving and transmitting antennas the recommendations have been presented.

• Counter: 689 | Comments : 0

The options of constructing the multipath receiving antenna systems based on APAA have been considered. The criteria for the selection of emitters for antennas of different range and purpose have been presented. It has been shown that the use of the phase shifters based on arsenide-gallium FET in the passive inclusion can reduce the consumption of control circuits without deterioration of the technical parameters. The estimates of the energy characteristics of three types of APAA have been given. The recommendations on the electromagnetic compatibility have been presented.

• Counter: 939 | Comments : 0

The research results of the I/Q-signals obtaining aspects in the receiving channel of smart antenna have been presented. The errors of signal processing in the array tract have been considered. The results of numerical modeling of the phase error influence on the smart antenna performance have been also presented.

• Counter: 1437 | Comments : 0

In radiolocation with the synthesized aperture the modulation of the probing signal using the pseudorandom sequences is actively used. This, as a rule, is due to tendency of the apparatuses miniaturization and simplification. The problem of increasing the dynamic range of the radar image of a region, obtained with synthetic aperture radar, has been considered. While using the pseudorandom sequences as the probing signals the dynamic range of an image has been determined by the level of side lobes of aperiodic autocorrelation functions (ACF). An original approach to reduce the level of the ACF pseudorandom sequences has been proposed. An analytic derivation of the sum of ACFs of N length pseudorandom sequence, obtained with a cyclic shift of the initial sequence, which side peaks of periodic ACF are equal to -1/ N , has been presented. The obtained result can be used in a radar design to form an ensemble of signals to provide a significant suppression of the integral side lobes level in comparison with a single sequence.

• Counter: 2388 | Comments : 0

The APAA based X-band airborne weather radar development results have been presented. It has been shown that the implemented APAA technology allows the ± 30 degree spatial scanning capability while reducing the radar weight and the overall dimensions. To increase resolution and to reduce the emitting power level, the digital formation of complex signals with big base has been used.

• Counter: 1431 | Comments : 0

The results of designing the radiating APAA aperture of the aircraft forward view radar for automatic guidance and landing of aircraft have been presented. It has been shown that the considered design methods allow a several times reduction of the number of receiving APAA active channels while conserving the main electric characteristics of the radar unit.

• Counter: 1405 | Comments : 0