Symmetric, shielded slow wave meander line
US6894656B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 2003 |
| Grant date | May 17, 2005 |
| Priority date | — |
| Expiry date | May 12, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01P5/02
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A standard slow wave meander line having sections of alternating impedance relative to a conductor plate is provided with a top shield connected to the conductor plane for the purpose of lowering the resonant frequency of narrow band antennas and lowering the low frequency cutoff limit of wide band antennas due to a higher delay per unit length occasioned by the use of the top shield. The shielded meander line may be utilized as a coupling device to truncated antennas such as a whip antenna or grounded loop antenna for the purposes of loading the antenna so as to provide lower frequency performance. Since the propagation constant of the meander line structure depends upon the number of high impedance/low impedance transitions per unit length, the utilization of the top shield results in more phase shifts per unit length and thus more delay per unit length, with the symmetric double sided version having double the number of transitions per unit length. When configured to provide a miniature antenna, the utilization of the top shield both lowers the cutoff frequency and eliminates down firing typical of wireless phone antennas due to the ground plane effect. Moreover, the top shield …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.