Single-Layer Patch Antenna With Nested Radiators for Dual-Band RHCP
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designing multiband uniplanar microstrip antennas is challenging due to issues like large area occupation, different phase centers, strong couplings, and reduced gain, especially when trying to create dual or multi-band antennas with radiators on the same substrate, and existing solutions like concentric microstrip rings face difficulties in impedance matching and increased coupling.
Innovation Solution
A multiband microstrip antenna design featuring a center shorted microstrip radiator enclosed by a shorted microstrip ring radiator, with multiple feed posts and a distribution network for quadrature phase generation, forming a cavity-backed antenna to achieve dual or multi-band operation with improved impedance matching and reduced coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two rectangular patches are placed side-by-side on the same substrate to achieve dual band operation, then the antenna can operate at two different frequencies, but it occupies a large area and generates strong couplings between patches
Solution Approach 1:
The patent implements a nested configuration where one patch is placed inside another concentric patch structure. The inner patch operates at one frequency band while the outer patch operates at another frequency band, allowing dual-band operation within a compact circular footprint rather than requiring side-by-side rectangular patches.
Solution Approach 2:
The patent introduces asymmetric feed structures and unequal spacing between the inner and outer patches to decouple their electromagnetic interactions. By making the feed positions and patch dimensions asymmetric, the strong couplings between patches are reduced while maintaining dual-band resonance characteristics.
2Adaptability or versatility
If two rectangular patches are placed side-by-side on the same substrate, then dual band operation is achieved, but the patches have different phase centers which degrades axial ratio for CP antennas
Solution Approach 1:
The patent employs asymmetric feed networks with unequal transmission line lengths and different feed positions relative to the patch centers. This asymmetric feeding strategy allows independent phase control for each patch, enabling the phase centers to be aligned or properly phased for circular polarization operation across both frequency bands.
Solution Approach 2:
The patent applies different feed configurations and local impedance transformations to the inner and outer patches. By optimizing the local feeding conditions for each patch independently, the phase centers can be controlled to coincide or maintain proper phase relationships for CP operation.
3Adaptability or versatility
If a concentric microstrip ring surrounds a second patch center to achieve dual band operation, then multi-band resonance is possible, but impedance matching to 50 ohms becomes difficult and coupling between radiators increases
Solution Approach 1:
The patent systematically varies key parameters including patch dimensions, feed line impedances, feed positions, and spacing between inner and outer patches to achieve both 50-ohm impedance matching and dual-band resonance. By optimizing these parameters, the concentric structure can be matched to standard 50-ohm connectors while maintaining resonant operation at two frequency bands.
Solution Approach 2:
The patent introduces intermediate matching structures such as transformation sections and coupling elements between the feed point and the patch radiators. These intermediary components facilitate impedance transformation from 50 ohms to the patch input impedances while minimizing direct coupling between the inner and outer patches.
4Productivity
If thick substrates are utilized to increase bandwidth of microstrip antennas, then bandwidth is improved, but antenna efficiency decreases due to surface wave propagation and power loss as heat
Solution Approach 1:
The nested concentric patch configuration inherently reduces surface wave excitation compared to traditional single-patch designs. The inner patch is electromagnetically coupled to the outer patch, creating a more distributed current distribution that reduces the excitation of TM0 surface waves, thereby maintaining efficiency even with thicker substrates for bandwidth enhancement.
Solution Approach 2:
The patent optimizes the substrate thickness parameter along with other geometric parameters to achieve the desired bandwidth while controlling surface wave losses. By carefully selecting and coordinating multiple parameters including patch dimensions, spacing, and substrate properties, the design achieves improved bandwidth without excessive efficiency degradation.
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 design achieves high efficiency, low coupling, and stable phase centers, enabling effective dual or multi-band operation with improved impedance matching and thermal performance, suitable for applications like GNSS receivers.
Implementation Method 1
The inner radiator is enclosed inside of the cavity formed of the first shorting wall which turns the inner radiator into a cavity backed antenna
Implementation Method 2
The outer microstrip ring radiator is shorted to ground at one of the edges using a first metalized shorting wall. The inner radiator is shorted to ground using a second shorting wall
Implementation Method 3
a center shorted microstrip radiator configured to radiate at a first (typically higher) frequency. An outer microstrip ring radiator surrounds the inner radiator and is configured to radiate at a second (typically lower) frequency
Implementation Method 4
Multiple feed posts are used to feed the radiators and a distribution network is placed on the back side of a substrate to provide the required power and quadrature phase to generate right-hand circularly polarized (RHCP) radiation
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A multiband microstrip antenna is provided. The antenna comprises of an inner ring radiator surrounded by an outer ring radiator on a first surface of a substrate. A feed network, on the second surface of the substrate, provides quadrature phases to feed posts to generate right hand circularly polarized (RHCP) signals.