Stacked Patch Antenna Cavities for Wide Dual-Band GNSS
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Solution Overview
Problem
Conventional patch antennas using ceramic substrates face challenges in size reduction and bandwidth narrowing due to the inverse proportionality of the quality factor Q with the physical volume, limiting their dual-band GNSS performance.
Innovation Solution
A stacked patch antenna design utilizing a molded ceramic puck with perforated air-cavities as the substrate, reducing effective permittivity and increasing the L1-band resonance volume without significant weight change, thereby widening the bandwidth and allowing flexibility in size and frequency control through cavity positioning and pattern manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If ceramic substrate is used to reduce antenna size, then the antenna size is reduced, but the bandwidth is narrowed
Solution Approach 1:
The patent introduces air cavities (perforations) within the ceramic substrate to create a porous structure. This reduces the effective permittivity of the substrate material, which in turn increases the resonant frequency and bandwidth of the antenna elements while maintaining the compact physical size provided by the ceramic material.
Solution Approach 2:
The patent creates a composite structure by combining ceramic material with air cavities. This composite approach allows the antenna to benefit from the low-profile characteristics of ceramic substrates while the air-filled cavities provide lower effective permittivity regions that expand the operational bandwidth.
2Adaptability or versatility
If stacked patches are used to cover dual-band requirements, then frequency coverage is improved, but the overall lateral size is determined by the bottom radiator
Solution Approach 1:
The patent applies local quality by creating regions of different effective permittivity within the substrate through selective placement of air cavities. This allows different areas of the substrate to support different resonant modes and frequencies, enabling dual-band operation without requiring the entire substrate area to be large enough for the lowest frequency resonance.
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 enhances bandwidth and reduces weight by altering the electromagnetic field distribution and impedance matching, enabling better control over the frequency ratio and harmonic radiation, thus improving dual-band performance.
Implementation Method 1
The effective permittivity in the perforated dielectric region is determined from the porosity, or void fraction of the perforation, defined as the fraction of the volume of the voids-space over the total bulk volume of the material.
Implementation Method 2
the fundamental mode's resonance frequency is given by f011=χ11/(2πa√εeq) where χ11 represents the first zero of the derivative of the Bessel function
Data Source
AI summary
A GNSS RHCP stacked patch antenna with wide dual band, high efficiency and small size is made of a molded high-permittivity material, such as ceramics, with a patterned cavity in the dielectric substrate. The perforated cavities in the substrate reduce the effective dielectric constant, increase the bandwidth and efficiency. The high-order modes can be manipulated through the design of cavities.