Bypass arrangement for low-noise amplifier

• US 20040008094A1
• Filed: 07/10/2003
• Published: 01/15/2004
• Est. Priority Date: 07/12/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Filtronic LK Oy
• Inventors: Niemi, Mika
• Granted Patent: US 6,927,646 B2
• Time in Patent Office: Days
• US Class Current: 333/101
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H

Abstract

An arrangement for bypassing a low-noise amplifier (LNA), intended especially to be used in base stations of mobile networks. For the bypass, a receiver antenna filter (210) has a second output (OUT2) parallel with a first output (OUT1) connected to the LNA. The antenna filter is of the resonator type, and there is a conductive element for each of its outputs in the resonator cavity. Selection between the LNA output signal and signal coming direct from the antenna filter is made by a changeover switch (SW). The noise figure of the receiver front stage (220) will improve as the series switch on the signal path, which most degrades the noise figure, is removed between the filter and LNA, and isolation on the LNA bypass path increases.

Claims

1. An arrangement for bypassing a low-noise amplifier in a radio receiver which comprises an antenna filter between said amplifier and antenna, and a bypass path for said amplifier, the arrangement comprising, at output side of said amplifier, a changeover switch for selecting a signal to be led along the signal path either from said amplifier or from the bypass path, said antenna filter having at least two parallel outputs the first of which is coupled direct to an input of said amplifier and the second of which is coupled direct to said bypass path.

2. The arrangement according to claim 1, said antenna filter being of the resonator type and having an output resonator, wherein for said outputs there is a conductive element of their own in the cavity of the output resonator to take signal energy out of the filter.

3. The arrangement according to claim 2, said conductive elements having substantially equally strong electromagnetic coupling to the output resonator.

4. The arrangement according to claim 1, the bypass path being a galvanic conductor connection.

5. The arrangement according to claim 1, comprising a second low-noise amplifier on the bypass path.

6. The arrangement according to claim 1, the changeover switch being implemented by PIN diodes.

7. The arrangement according to claim 1, the changeover switch being implemented by MEMS switches.

8. The arrangement according to claim 1, the changeover switch being implemented by MMIC technology.

9. The arrangement according to claim 1, the changeover switch being implemented by a relay.