| Radio Frequency Systems, Inc. Patent applications |
| Patent application number | Title | Published |
|---|
| 20110032854 | SYSTEM AND METHOD FOR TDD/TMA WITH HYBRID BYPASS SWITCH OF RECEIVING AMPLIFIER - An arrangement of hybrid couplers, selectively removing RF amplifiers from a receiving path from an antenna back to a receiver in response to an event, the event switching impedances of switchable impedances connecting to ports of the hybrid couplers, between a matching impedance and mismatching impedance. The matching and mismatching impedances change coupling characteristics of the hybrid couplers between a normal coupling and a bypass coupling. In the normal coupling the hybrid couplers provide port-to-port coupling placing the RF amplifiers within the receiving path and, in the bypass coupling, the hybrid couplers provide port-to-port coupling bypassing the RF amplifiers. Optionally, transmitted signal power is detected to identify transmit and receiving intervals. During detected transmit intervals, isolation switches isolate the RF amplifiers from the feedback path and, during receiving intervals and, during detected receiving intervals, the isolation switches RF amplifiers into the feedback path to amplify reception signals. Optionally a hybrid coupler switch is placed between the two circulators to increase the isolation in the RX mode reducing feedback to the LNA's. | 02-10-2011 |
| 20100188174 | COMPACT TUNABLE DUAL BAND STOP FILTER - Various exemplary embodiments include a technique for tuning a filter to have two stop bands. This technique may involve combination of signals from a plurality of high-band notch resonators and low-band notch resonators. Loop wires may couple both high-band and low-band notch resonators to a central conductor, thereby enabling the central conductor to transmit a signal having dual stop bands. | 07-29-2010 |
| 20100127801 | LOW PASS FILTER WITH EMBEDDED RESONATOR - An embedded resonator sharpens the frequency characteristics of a coaxial low pass filter. The resonator introduces finite transmission zeros to the response of the low pass filter, thereby suppressing spurious modes occurring just above the operating frequency. Two parameters are used to tune the operation of the embedded resonator. The length of an insert into the filter's transmission line substantially controls the resonant frequency, and the gap width substantially controls the coupling of the embedded resonator to the low pass filter. | 05-27-2010 |
