# US 8,570,235 B2 · Systems and methods for complementary metal-oxide-semiconductor (CMOS) differential antenna switches using multi-section impedance transformations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,235 B2 - Document ID: US8570235B2 - Status: Granted - Kind: B2 - Application number: 12/773,222 - Filed: 2010-05-04 - Published: 2011-11-10 - Granted: 2013-10-29 - Earliest claimed: 2010-05-04 - Assignees: Samsung Electro-Mechanics Co., Ltd. - Applicants: Minsik Ahn; Chang-Ho Lee - Inventors: Minsik Ahn; Chang-Ho Lee - Web page: https://patentgrep.com/patent/US8570235B2 ## CPC - H01Q 1/50: Structural association of antennas with earthing switches, lead-in devices or lightning protectors - H01Q 3/24: varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract Example embodiments of the invention are directed to CMOS differential antenna switches with multi-section impedance transformation. The differential architecture can provide relief from large voltage swings of the power amplifiers by distributing the voltage stress over the receiver switch with two of the identical or substantially similar single-ended switches. In order to reduce the voltage stress further, multi-section impedance transformations can be used. Degraded insertion loss due to the impedance transformation technique can be compensated by selecting an optimal impedance for the antenna switch operation. Accordingly, the use of the multi-section impedance transformations with the differential antenna switch architecture enables high power handling capability for the antenna switch with acceptable efficiency for the transmitter module. ## Claims ### Claim 1 A system for an antenna switch, comprising: at least one differential amplifier that generates differential outputs; a differential antenna switch block, wherein the differential antenna switch block includes at least a first single-ended switch and a second single-ended switch; a first matching network to provide a first impedance transformation between the at least one differential amplifier and the differential antenna switch block, wherein the first matching network communicates each of the differential outputs of the at least one differential amplifier to respective ones of the first and second single-ended switches; and a second matching network to provide a second impedance transformation between the differential antenna switch block and at least one antenna, wherein the second matching network receives differential signals from the differential antenna switch block, and provides at least one system output signal to the at least one antenna; wherein the first impedance transformation and the second impedance transformation collectively provide a total impedance transformation to match a first impedance of the differential amplifier with a second impedance of the at least one antenna, and further wherein each of the first single-ended switch and the second single-ended switch comprise: a series receive switch operable to selectively connect or disconnect a main receive signal path between the at least one antenna and a receiver (RX) block, wherein the series receive switch includes a plurality of first transistors; a shunt receive switch operable to selectively connect or disconnect the main receive signal path to or from ground; a series transmit switch operable to selectively connect or disconnect a main transmit signal path between a transmitter (TX) block and the at least one antenna; and a shunt transmit switch operable to selectively connect or disconnect the main transmit signal path to or from ground, wherein the shunt transmit switch includes a plurality of second transistors. ### Claim 2 (depends on 1) The system of claim 1, wherein during a transmit mode, the series transmit switch and the shunt receiver switch are enabled, and the shunt transmit switch and the series receive switch are disabled, and wherein during a receive mode, the series receive switch and the shunt transmit switch are enabled, and the series transmit switch and the shunt receiver switch are disabled. ### Claim 3 (depends on 1) The system of claim 1, wherein the RX block includes at least one low-noise differential amplifier, wherein the main receive signal path between the first antenna and the RX block includes at least a portion of the second matching network, wherein the TX block includes at least one differential power amplifier, wherein the main transmit signal path between the transmitter (TX) block and the second antenna includes at least a portion of the first matching network and the second matching network. ### Claim 4 (depends on 1) The system of claim 1, wherein at least one of the first transistors or the second transistors are MOSFETs. ### Claim 5 (depends on 1) The system of claim 1, wherein the at least one differential amplifier, the first matching network, the differential antenna switch block, and the second matching network operate with a differential architecture, wherein the differential architecture increases power handling capability of the differential antenna switch block. ### Claim 6 (depends on 1) The system of claim 1, wherein multi-section impedance transformation provided by the first and second impedance transformations of the first and second matching networks increases an efficiency of a transmitter module comprising at least one differential power amplifier and the differential antenna switch block. ### Claim 7 (depends on 1) The system of claim 1, wherein the at least one system output signal includes a first system differential output signal and a second system differential output signal, wherein the at least one antenna comprises a first differential antenna for receiving the first system differential output signal, and a second differential antenna for receiving the second system differential output signal. ### Claim 8 (depends on 1) The system of claim 1, wherein the second matching network further includes a balun for converting the received differential signals into a single-ended system output signal, wherein the at least one antenna includes a single-ended antenna for receiving the single-ended system output signal. ### Claim 9 (depends on 1) The system of claim 1, wherein the at least one differential amplifier includes a plurality of differential amplifiers, wherein the first matching network includes at least one transformer for performing power combining of the differential outputs of the plurality of differential amplifiers. ### Claim 10 A CMOS differential antenna switch comprising two single-ended antenna switches for operating with respective first and second differential signals, wherein each single-ended antenna switch comprises: a respective series receive switch operable to selectively connect or disconnect a respective main receive signal path between at least one antenna and a receiver (RX) block, wherein the respective series receive switch includes a respective plurality of first transistors; a respective shunt receive switch operable to selectively connect or disconnect the respective main receive signal path to or from ground; a respective series transmit switch operable to selectively connect or disconnect a respective main transmit signal path between a transmitter (TX) block and the at least one antenna; and a respective shunt transmit switch operable to selectively connect or disconnect the respective main transmit signal path to or from ground, wherein the respective shunt transmit switch includes a respective plurality of second transistors. ### Claim 11 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the at least one antenna comprises a pair of differential antennas, including a first antenna and a second antenna, wherein the first antenna is connectable by a first of the two single-ended antenna switches, and wherein the second antenna is connectable by a second of the two single-ended antenna switches. ### Claim 12 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the at least one antenna includes a single antenna, wherein a matching network having a balun is provided between the single antenna and the two single-ended antenna switches for converting between the first and second differential signals and a single-ended signal available at the single antenna. ### Claim 13 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the balun includes an LC balun having at least one inductor and at least one capacitor. ### Claim 14 (depends on 10) The CMOS differential antenna switch of claim 10, wherein during a transmit mode, the respective series transmit switch and the respective shunt receiver switch are enabled, and the respective shunt transmit switch and the respective series receive switch are disabled, and wherein during a receive mode, the respective series receive switch and the respective shunt transmit switch are enabled, and the respective series transmit switch and the respective shunt receiver switch are disabled. ### Claim 15 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the TX block includes the at least one differential power amplifier, wherein the respective main transmit signal path between the transmitter (TX) block and the at least one antenna includes a first matching network and a second matching network, wherein the first matching network provides a first impedance transformation between the at least one differential power amplifier and the two single-ended antenna switches, wherein the second matching network provides a second impedance transformation between the two single-ended antenna switches and the at least one antenna. ### Claim 16 (depends on 15) The CMOS differential antenna switch of claim 15, wherein the at least one differential power amplifier includes a plurality of differential power amplifiers, wherein the first matching network includes a transformer for performing the first impedance transformation and for combining output powers of the plurality of differential power amplifiers. ### Claim 17 (depends on 15) The CMOS differential antenna switch of claim 15, wherein multi-section impedance transformation provided by the first and second impedance transformations of the first and second matching networks increases an efficiency of a transmitter module comprising at least the differential power amplifier the two single-ended antenna switches, wherein the two single-ended antenna switches are provided according to a differential configuration to increase a power handling capability of the CMOS differential antenna switch. ### Claim 18 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the plurality of first transistors or the plurality of second transistors are in a stacked configuration in which transistors are stacked from respective sources to respective drains. ### Claim 19 (depends on 10) The CMOS differential antenna switch of claim 10, wherein the respective series receive switch, the respective shunt receive switch, the respective series transmit switch, and the respective shunt transmit switch are implemented using MOSFETs.