Multi leveled active antenna configuration for multiband MIMO LTE system
An active antenna system and algorithm is described that provides for dynamic tuning and optimization of antenna system parameters for a MIMO system where correlation and isolation between antennas in the system are dynamically altered to provide for greater throughput. As one or multiple antennas are loaded or de-tuned due to environmental changes, corrections to correlation and/or isolation are made by selecting the optimal antenna radiation pattern and by adjusting electrical length and/or reactive loading of transmission lines connecting the antennas. Multiple Isolated Magnetic Dipole (IMD) antennas are co-located and connected with a feed network that can include switches that adjust phase length for transmission lines connecting the antennas. Filtering is integrated into the feed network to improve rejection of unwanted frequencies. Filtering can also be implemented on the antenna structure.
1. An antenna system, comprising:
a first active modal antenna adapted for operation at a plurality of first antenna modes, each of said first antenna modes having a distinct antenna radiation pattern;
a second active modal antenna adapted for operation at a plurality of first second antenna modes, each of said second antenna modes having a distinct antenna radiation pattern;
a processor coupled to the first and second modal antennas and configured to vary antenna modes thereof;
at least one conductor coupling the first modal antenna with the second modal antenna in a multi-input multi-output (MIMO) configuration; and
one or more active tuning blocks coupled to at least one of said first and second modal antennas, said active tuning blocks individually comprising one or more switches, filters, tunable components or passive components for altering a length of the conductor connecting the first and second modal antennas; and
said processor further coupled to the one or more active tuning blocks and adapted to generate control signals for communicating therewith for configuring the active tuning blocks; and
at least one of said first and second active modal antennas comprising:
a driven antenna element positioned above a circuit board forming an antenna volume therebetween,
a first parasitic element positioned within the antenna volume and coupled to a first active element, the first parasitic element and first active element being configured to induce a shift in a frequency response of the driven antenna element, and
a second parasitic element positioned outside of the antenna volume and adjacent to the driven element and coupled to a second active element, the second parasitic element and second active element being configured for steering the radiation pattern of the driven antenna element.
2. The antenna system of claim 1 , comprising memory containing a database of records wherein information for configuring said first and second modal antennas and said one or more active tuning blocks is stored in said database.
3. The antenna system of claim 2 , comprising sensors adapted to determine a use case of the antennas, wherein said sensors communicate the use case to said processor, and wherein said database is accessed to determine optimized parameters for configuring the antenna system.
4. The antenna system of claim 3 , comprising an algorithm stored in said memory, said algorithm programmed to analyze loading data from said sensors and generate control signals for communicating with the modal antennas.
5. The antenna system of claim 4 , said algorithm adapted to process signals from said sensors and estimate a loading profile of the wireless device; said antenna system further adapted to lookup said database records and estimate the loading of the device; and said processor adapted to generate control signals for adjusting tunable components in the active modal antennas and the active filter blocks for optimizing the antennas.
6. The antenna system of claim 1 , further comprising a passive antenna.
7. The antenna system of claim 1 , comprising three or more modal antennas.
8. The antenna system of claim 1 , wherein each of said active modal antennas comprises one or more tunable components.
9. The antenna system of claim 8 , wherein said tunable components are individually selected from the group consisting of: a switch, FET, MEMs device, tunable inductor, and a tunable capacitor.