Multiband Coaxial Horn Antenna Source for Monopulse Radar
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reflector antennas face challenges in minimizing power coupling between sum and difference channels, leading to ohmic losses and reduced efficiency, especially when trying to maintain frequency bandwidth and multiband compatibility.
Innovation Solution
A reflector antenna source with a pseudo-cavity excited by two orthogonal TE 11 modes for the sum channel and TE 21 modes for the difference channel, using a difference power supply circuit with eight probes distributed around the main emission axis, where the terminal supply branches create a standing wave with an electric field node at the branching point and a magnetic field node at each probe, isolating the difference channel from the sum channel and reducing ohmic losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If peripheral radiating elements are brought closer to the central waveguide to create intersecting beams for suitable deviometric slope, then tracking accuracy is improved, but power coupling between sum and difference channels increases causing ohmic losses
Solution Approach 1:
The patent introduces an intermediate structure (the specific geometric configuration of the horn antenna with defined aperture dimensions and feed position) that mediates between the central waveguide and peripheral elements, enabling beam intersection for accurate tracking while controlling power coupling to minimize ohmic losses
Solution Approach 2:
The patent optimizes specific geometric parameters (aperture diameter, feed position, horn length) to achieve the desired balance between tracking accuracy and power coupling. By carefully selecting these parameters, the system achieves suitable deviometric slope while limiting power transfer to 15-25%
2Measurement precision
If peripheral elements are positioned closer to central waveguide to achieve small angular beam intersection, then angular difference measurement is improved, but power coupling increases causing efficiency reduction
Solution Approach 1:
The patent modifies geometric parameters (aperture size, feed positioning, horn dimensions) to achieve optimal beam intersection angles for accurate angular measurement while controlling the degree of power coupling to maintain source efficiency
3Reliability
If low-noise amplifiers are added to each radiating element to compensate for ohmic losses, then signal quality is improved, but sum channel efficiency drops reducing figure of merit
Solution Approach 1:
The patent takes preliminary action by optimizing the geometric configuration to minimize power coupling and ohmic losses before signal degradation occurs, eliminating the need for compensatory amplifiers that would harm sum channel efficiency
Solution Approach 2:
The patent converts the potential harm of power coupling into a benefit by carefully controlling it to achieve the necessary beam intersection for accurate tracking while keeping losses acceptable, thereby maintaining overall system efficiency without requiring additional amplification
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for efficient restoration of the sum channel signal without loss, maintains phase coherence, and extends antenna operation to multiple frequency bands, surpassing the Stein limit by transforming coupled energy into re-radiated energy in phase with the central element, thereby enhancing efficiency beyond theoretical predictions.
Implementation Method 1
the terminal branches are dimensioned such that a coupling of the sum channel signal with the eight excitation probes of the difference channel generates a standing wave on the terminal supply branches
Implementation Method 2
a pseudo-cavity, a first sigma excitation device for exciting the pseudo-cavity according to two orthogonal TE 11 modes so as to generate a sum channel signal via a coaxial waveguide, a second excitation device for exciting the pseudo-cavity according to two TE modes 21
Data Source
Figure 1
Figure 2~2bis
Figure 3
AI summary
The invention relates to a source (1) for a reflector antenna, comprising: - a pseudo-cavity (100), - a first sigma excitation device (10) for exciting the pseudo-cavity (100) in such a way as to generate a sum channel signal via a coaxial waveguide (400), - a second excitation device (20) for exciting the pseudo-cavity (100) in such a way as to generate a difference channel signal, the second device (20) comprising eight probes (8) angularly distributed around a principal emission axis (A) of the source (1), and a difference supply circuit (25) for supplying the eight excitation probes (8) according to the two modes TE21.