L-Shaped Feed for Microstrip Antenna Matching Network
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Solution Overview
Problem
Microstrip patch antennas with existing proximity coupled feed mechanisms, such as L-shaped feeds, face challenges in achieving wideband operation and directional current distribution, leading to inefficient electromagnetic field distribution and high back radiation.
Innovation Solution
A microstrip patch antenna design featuring a two-layer laminate structure with an L-shaped feed mechanism, including a pin and stub configuration, where a clearance gap around the pin on the top layer and a matching network on the bottom layer reduce shunt inductance and series capacitance, enabling 50 ohm wideband operation and stable, directional current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional proximity coupled feed mechanisms are used, then the antenna structure is simple, but the bandwidth is limited and current distribution is non-directional
Solution Approach 1:
The feed structure is segmented into distinct functional components: the L-shaped probe with pin and stub, the laminate structure with substrate and metal layers, and the clearance gap. This segmentation allows each component to be optimized independently for its specific function, enabling wideband operation while maintaining manufacturing feasibility.
Solution Approach 2:
The invention transitions from a conventional planar feed structure to a three-dimensional L-shaped probe configuration that extends through the laminate structure. This dimensional change enables proximity coupling with the top layer while providing independent control of electrical parameters through the probe's length, width, and position, achieving wideband operation.
2Object-generated harmful factors
If conventional feed mechanisms are used, then manufacturing is easier, but electromagnetic field distribution is inefficient with high back radiation
Solution Approach 1:
The L-shaped probe configuration introduces asymmetry in the feed structure, with the pin and stub extending in perpendicular directions. This asymmetric geometry creates directional current distribution on the top layer, focusing radiation broadside to the antenna and reducing back radiation, while remaining manufacturable using standard PCB and antenna fabrication techniques.
3Adaptability or versatility
If the clearance gap and matching network are added, then wideband operation is achieved, but the device complexity increases
Solution Approach 1:
The matching network functionality is merged into the feed structure itself. The L-shaped probe's pin and stub, combined with the clearance gap and laminate structure, collectively provide impedance matching across the bandwidth. This integration eliminates the need for separate matching components, achieving wideband operation without proportionally increasing complexity.
4Stability of the object's composition
If proximity coupling is used to excite currents, then current distribution becomes stable and directional, but the feed mechanism complexity increases
Solution Approach 1:
The L-shaped probe acts as an intermediary between the feed source and the top layer currents. The pin and stub configuration provides controlled proximity coupling that mediates energy transfer, creating stable and directional current distribution on the top layer while maintaining a relatively simple overall feed structure that can be manufactured using conventional techniques.
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 wideband performance and improved front-to-back radiation ratio by focusing radiated energy broadside, reducing back radiation and maintaining a high front-to-back ratio with minimal size constraints on the ground plane base.
Implementation Method 1
the L-shaped feed mechanism excites the currents on the top layer via proximity coupling (no direct connection)
Implementation Method 2
the clearance member around the pin effectively decreases shunt inductance and reduces a series capacitance at a feed point
Implementation Method 3
the stub member reduces the shunt inductance close to the feed point
Data Source
AI summary
A microstrip patch antenna including a ground plane base, an L-shaped feed structure and a laminate structure is disclosed herein. A matching network is formed by a clearance member of the laminate structure around a pin and a stub of the L-shaped feed structure on the bottom surface in which the clearance member around the pin effectively decreases shunt inductance and reduces a series capacitance at a feed point to enable a 50 ohm wideband operation.