DE3323234A1 - Phase-controlled group antenna - Google Patents

Abstract

Production-related phase errors in the signal paths of a phase-controlled group antenna corrupt the phase allocation of the aperture field which is required to achieve a specific polar diagram. By measuring the phase error for each aerial element, storing the phase error as a correction value and superimposing the stored correction value for setting the phase shift in accordance with the desired diagram, the desired phase allocation can be achieved with high accuracy even in the case of low requirements on production tolerances. It is particularly advantageous to determine and store the correction values with a higher accuracy than is possible for setting the phase shifters. This considerably reduces the systematic quantisation error of digitally-controlled group antennas.

Description

Phased array antenna

The invention relates to a phased array radar antenna with digitally adjustable phase shifters for electronic diagram panning Such antennas have a particular flexibility in setting almost any diagram shape. For a specific shape and orientation of the antenna diagram the corresponding phase allocation of the antenna aperture can be determined according to known algorithms to calculate. The calculated values are used to set the digitally adjustable Phase shifter used. Phase error compared to the occupancy of the aperture field the calculated target occupancy arise z. B. due to the tolerance of decoupling slots a feed line and electrical lengths of the feed lines. To the resulting Keeping phase errors sufficiently small by means of mechanical precision are precise Compliance with manufacturing tolerances and extensive reworking for trimming Cable lengths and the like required.

The object of the present invention is to achieve with little effort an antenna of the type mentioned above resulting from manufacturing tolerances To avoid phase errors in the antenna aperture.

The invention is described in claim 1. The subclaims include advantageous embodiments of the invention.

The requirement for mechanical precision can be met by the inventive electronic phase correction can be noticeably reduced. The through manufacturing tolerances phase deviations of the signal paths to the individual radiators (with two-dimensional electronic diagram setting) or for individual heater lines (with one-dimensional Diagram setting) from the setpoint value can be changed by measuring the phase in front of the radiators (resp. Emitter rows) of the fully assembled antenna can be measured. The measured phase errors are stored as correction values in a read-only memory (ROM) and when setting the diagram calculated for the desired shape and direction of the antenna diagram Setting values for the digital setting of the phase shifter are superimposed.

When the phase errors of the signal paths have a significant frequency dependence show, the correction values are advantageously also dependent on the Frequency saved.

Because the phase errors in the supply lines to the individual radiator elements are independent of the diagram form and the variety of possible diagram settings phase error measurement and storage for each setting not allows the phase errors at a certain diagram setting, preferably measured with homogeneous phase occupancy of the aperture field. With this diagram setting the phase shifter remains due to the digital setting (quantization) a phase error of a maximum of half the step size, which does not continue at the same time the setting option of the phase shifter, with binary coding of the setting value aleo + 1 LSB (LSB = 3r least significant bit). When setting a different radiation direction or diagram form can be created by quantizing the correction value and the desired diagram calculated value results in a total error of t 1 LSB.

A particularly advantageous embodiment of the invention provides for remedial action this increased phase error propose the correction values with higher accuracy save as it corresponds to the resolution of the phase shifter. As a result of consideration the places exceeding the resolution of the phase shifter become a further quantization errors avoided through the correction. There remains a maximum phase error of half the step size of the phase shifter setting when the correction value is available with the same accuracy only by halving the step size of the phase shift adjustability, thus could be achieved by adding a further bit per phase shifter were. The additional storage space requirement is with the for. Available electronic To achieve memory modules cheaply and with little effort, whereas the expansion of all phase shifters by 1 bit setting accuracy a considerable increase in the cost of Antenna effects. The final setting values for the phage shifters result from the corrected setting values by rounding off those exceeding the setting accuracy Bits.

Claims (4)

Claims phase-controlled radar group antenna with digital adjustable phase shifter for electronic diagram tilting, characterized in that that phase deviations of the signal paths to the individual radiator elements from the Target phase are stored in digital form as correction values and the stored Values of the setting of the phase shifter according to the desired diagram are superimposed. 2. group antenna according to claim 1, characterized in that the Correction values are stored depending on the frequency. 3. Group antenna according to claim 1 or 2, characterized in that that the correction values are stored with a higher accuracy than the setting the phase shifter is possible. 4. group antenna according to claim 3, characterized in that the The setting values of the phase shifter and the correction values are binary-coded and the Correction values are at least two bits more precise than the setting of the Phase shifter is possible.