Patch Array Radiometer Antenna for Stable UAV Microwave Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microwave radiometers for UAVs suffer from unstable electronics, large and heavy antennas, radiofrequency interference, and inadequate polarization measurement capabilities, leading to inaccurate soil moisture and other parameter retrievals.
Innovation Solution
A lightweight, low-power radiometer with a dual-polarization patch array antenna and optimized radiometer electronics, featuring air gaps and analog bandpass filters, direct-detection, and internal calibration, to enhance measurement accuracy and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard patch antenna or colinear dipole array is used, then the device complexity is reduced, but the antenna gain is lower and loss is higher
Solution Approach 1:
The patent employs a composite antenna structure combining patch elements with specific geometric configurations and material arrangements to achieve superior gain and efficiency compared to standard patch antennas, while maintaining manufacturing feasibility through systematic design
2Loss of energy
If standard patch antenna is used, then the device complexity is reduced, but the antenna gain is lower
Solution Approach 1:
The composite antenna design integrates multiple patch elements with optimized geometric configurations and material properties to simultaneously achieve high gain, low loss, and stable measurement performance, resolving the trade-off between manufacturing simplicity and measurement reliability
3Object-affected harmful factors
If digital backend is used for post-processing, then the RFI filtering capability is improved, but the electronics stability deteriorates due to local-oscillator drift
Solution Approach 1:
The patent implements preliminary filtering of radiofrequency interference through analog bandpass filters positioned before the digital backend, preventing RFI from saturating amplifiers and compromising the signal before it reaches the digital processing stage, thereby maintaining both RFI filtering capability and electronics stability
4Device complexity
If single polarization measurement is used, then the device complexity is reduced, but the information content for soil moisture retrieval is insufficient
Solution Approach 1:
The patent segments the polarization measurement function into two independent orthogonal linear polarization channels, each with dedicated antenna elements and signal processing paths, enabling comprehensive soil moisture retrieval while maintaining manageable system complexity through modular architecture
5Device complexity
If dual polarization is measured with the same antenna, then the device complexity is reduced, but correlation and cross-talk occur making independent measurements difficult
Solution Approach 1:
The patent physically segments the dual-polarization measurement function into two separate antenna systems, each optimized for one polarization direction, eliminating correlation and cross-talk between channels while maintaining reasonable system complexity through independent but coordinated antenna designs
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
The solution provides stable, accurate, and efficient microwave brightness temperature measurements, enabling precise soil moisture and other parameter retrievals, suitable for UAV-based applications and ground use, with reduced interference and improved resolution.
Implementation Method 1
a radiometer with an improved highly-efficient and directional low-mass antenna... capable of air-borne measurement from UAVs
Implementation Method 2
Low-mass low-power microwave radiometer sensing natural emission in the passive-protected microwave spectrum of 1400-1427 MHz
Data Source
Figure 1a~1b
Figure 2
AI summary
The disclosed invention shows a portable stable low-mass microwave radiometer (0) for measuring microwaves in the spectral range between 1 and 300 GHz, comprising at least one patch array antenna (1) and a connected suitable electronics (2) with radio-frequency components and signal processing components, allowing more stable and more accurate measurements of brightness temperature while in particular mounted on an unmanned aerial vehicle (UAV). This is reached with a patch array antenna (1) comprising at least one patch array (10, 10') with a patch substrate layer (100, 100') of a dielectric material with a pattern of an even number of printed patches (101, 101') on a front side is printed, while printed patches (101, 101') are connected via inset-feds to striplines, wherein connector lines are connected to the striplines to be led from a backside of the patch substrate layer (100, 100') to and through a ground conductor layer (108, 108'), which is fixed to the backside of the patch substrate layer (100, 100') in a defined distance (d, d') forming an air gap (106, 106') between both layer (100, 100', 108, 108') by a multiplicity of spacers (107, 107').