Tilted Conical Helical Antenna Array for Constant Gain
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Solution Overview
Problem
Conventional antenna arrays face challenges in maintaining constant gain and radiation patterns over a frequency band while having a lower height profile, as existing helical antennas often exhibit varying performance across different frequencies.
Innovation Solution
The antenna array employs at least two conical helical antennas, with at least one being a tilted conical helical antenna, modeled on a frustum of an oblique cone, where the tip angle and distances between the planar surfaces determine the bandwidth and frequency operation, ensuring a consistent pitch angle and handedness across all antennas, and phase shifters are used to maintain phase alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional helical antennas are used in an array, then the antenna can operate over a frequency band, but the gain and radiation pattern vary across different frequencies
Solution Approach 1:
The patent applies local quality by tilting the conical helical antennas at specific angles relative to the array axis. This local geometric modification creates different electrical lengths and phase characteristics for antennas at different positions in the array, which compensates for frequency variations and maintains constant gain and radiation pattern across the operating bandwidth.
Solution Approach 2:
The patent changes the geometric parameters of the helical antennas, specifically the tilt angle of the conical axis and the pitch angle of the helix. By adjusting these parameters, the electrical characteristics of the antennas are modified to achieve frequency-invariant performance, transforming the antenna array from frequency-dependent to frequency-independent operation.
2Length of stationary object
If the height of the antenna array is reduced, then a lower profile is achieved, but maintaining constant gain and radiation pattern becomes more difficult
Solution Approach 1:
The patent reduces the physical height of the antenna array by optimizing the conical frustum dimensions and helical parameters. The tilt angle and pitch angle are carefully selected to maintain the electrical length requirements for constant performance while minimizing the mechanical height, achieving both compact size and frequency-invariant radiation characteristics.
Solution Approach 2:
The patent introduces the tilt angle dimension as a new degree of freedom in the antenna geometry. By tilting the conical axis away from the vertical direction, the antenna achieves additional phase control capability that compensates for the reduced height, maintaining constant gain and radiation pattern with a lower profile than conventional vertical helical arrays.
3Reliability
If tilted conical helical antennas are used, then constant gain and radiation pattern are achieved, but the antenna structure becomes more complex
Solution Approach 1:
The patent employs asymmetric tilting of the conical helical antennas, where each antenna is tilted at a specific angle relative to the array axis rather than being vertically aligned. This asymmetric configuration creates the necessary phase differences for frequency-invariant performance. While the geometry is asymmetric, the overall array structure remains relatively simple, avoiding the need for complex feed networks or active phase control systems.
Data Source
AI summary
The invention is directed to an antenna array comprised of conical helical antennas with at least one of the antennas being a tilted conical helical antenna. In one embodiment, a tilted conical helical antenna in the array comprises an electrically conductive wire that follows a helical path on a frustum of an oblique elliptical cone in which the axis of the cone is tilted relative to the planar base surface of the cone (i.e., not perpendicular or parallel to the surface) in a plane defined by the axis and a phase center axis of the array. Each of the tilted conical helical antennas in an array is spaced from the phase center axis of the array. The degree of tilt increases the farther an antenna is located from phase center axis.