Folded UWB Antenna Impedance Bandwidth Extension
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Solution Overview
Problem
Conventional ultra-wideband (UWB) antennas have a high profile, making them unsuitable for small-sized personal communication devices such as mobile phones and personal digital assistants, which limits their application in compact designs.
Innovation Solution
A small size UWB antenna design featuring a radiation element, dielectric substrate, and matching element, where the signal feeding element is formed on the upper and lower surfaces, allowing for variations in the location and type of the radiation element and matching element, such as air gap slots or electrical connections, to extend impedance bandwidth and facilitate surface-mountable fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional monopole or dipole UWB antenna designs are used, then sufficient impedance bandwidth is achieved, but the antenna profile becomes too large for compact personal communication devices
Solution Approach 1:
The patent transitions from conventional planar monopole/dipole configurations to a three-dimensional folded structure. The radiation element is folded back on itself multiple times, creating vertical and lateral dimensions that enable sufficient electrical length and impedance bandwidth within a compact footprint. This dimensional transformation allows the antenna to achieve UWB performance without requiring a large planar profile.
Solution Approach 2:
The folded radiation element structure effectively nests the antenna conductor within a compact volume. By folding the radiation element back on itself and positioning it within the antenna housing space, the design achieves a nested configuration where the conductive path is contained within a small external envelope, reducing the overall antenna profile while maintaining functional length.
2Reliability
If the radiation element is made larger to achieve sufficient bandwidth, then impedance matching improves, but the antenna becomes unsuitable for surface-mountable fabrication in small devices
Solution Approach 1:
The folded structure utilizes vertical stacking and three-dimensional routing to achieve sufficient electrical length without increasing planar dimensions. This allows the antenna to maintain a compact profile suitable for surface-mount fabrication while achieving the electrical performance required for proper impedance matching across the UWB spectrum.
Solution Approach 2:
The patent employs adjustable geometric parameters in the folded structure, such as fold angles, segment lengths, and spacing between folded sections. These parameters can be optimized to achieve the desired impedance matching characteristics while maintaining a compact form factor suitable for surface-mount fabrication processes.
Data Source
AI summary
A small size ultra-wideband (UWB) antenna comprises a radiation element, a dielectric substrate, and a dielectric element. The radiation element includes a radiation conductor, a matching element, and an antenna feeding element. A signal feeding element and a conductor plane are formed on the upper and lower surfaces of the dielectric substrate, respectively. With the matching element on the radiation conductor, the current distribution on the conductor plane is changed so that the antenna achieves a sufficient extension for both high and low impedance bandwidths. The UWB antenna is also suitable for surface-mountable fabrication process, which effectively reduces the manufacturing cost. The antenna has the advantages of small size, simple structure, and an impedance bandwidth of 7.97 GHz.