Narrow band-pass tuned resonator filter topologies having high selectivity, low insertion loss and improved out-of-band rejection over extended frequency ranges
US7078987B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1999 |
| Grant date | Jul 18, 2006 |
| Priority date | — |
| Expiry date | Sep 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/1775
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A tuned resonator circuit topology is disclosed that permits implementation of narrow band-pass filters having high loaded Q and optimal coupling (for low insertion loss) using a parallel tuned resonator topology at frequencies in the 1 to 2 GHz range and beyond. The topology consists of a mirror image of the parallel tuned circuit about the signal line of a conventional parallel tuned circuit to effect a cancellation of virtually all of the induced currents between the inductive elements of the resonators. This reduction in induced currents reduces the magnetic coupling between the resonators, thereby offsetting the increase in overall coupling between the resonators as frequency increases, and thereby serves to maintain optimal coupling between the resonators as the frequency of operation increases. Moreover, the mirror image topology increases the parallelism between the inductive elements in the resonators, thereby decreasing the inductance values and permitting an increase in capacitance values. Increasing the capacitance values of the resonators effectively offsets the decrease in the loaded Q as frequency is increased. The topology works for any number of parallel resonators…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.