# US 10,320,441 B2 · Systems and methods for a switchless radio front end > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,320,441 B2 - Document ID: US10320441B2 - Status: Granted - Kind: B2 - Application number: 15/784,957 - Filed: 2017-10-16 - Published: 2018-02-08 - Granted: 2019-06-11 - Earliest claimed: 2016-06-20 - Assignees: Ubilite, Inc. - Applicants: Ubilite, Inc. - Inventors: Ismail Lakkis - Web page: https://patentgrep.com/patent/US10320441B2 ## CPC - H03F 3/45475: {using IC blocks as the active amplifying circuit} - H04B 1/44: Transmit/receive switching - H03F 3/19: with semiconductor devices only - H03F 3/195: in integrated circuits - H03F 3/217: Class D power amplifiers; Switching amplifiers - H03F 3/245: {with semiconductor devices only} - H03F 3/45071: {with semiconductor devices only} - H03F 3/45179: {using MOSFET transistors as the active amplifying circuit (H03F3/45278 takes precedence)} - H03F 3/45188: {Non-folded cascode stages} - H03F 2200/294: the amplifier being a low noise amplifier [LNA] - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2200/537: A transformer being used as coupling element between two amplifying stages - H03F 2200/541: Transformer coupled at the output of an amplifier - H03F 2203/45: Indexing scheme relating to differential amplifiers - H03F 2203/45228: A transformer being added at the output or the load circuit of the dif amp - H03F 2203/45731: the LC comprising a transformer - H03F: AMPLIFIERS - H04B: TRANSMISSION ## Abstract A radio circuit, comprises an antenna; a differential power amplifier, comprising differential transmit inputs and differential transmit outputs, configured to amplify differential transmit signals received via the differential transmit inputs and output the amplified differential transmit signals via the differential transmit outputs; a differential low noise amplifier, comprising differential receive inputs and differential receive outputs, configured to receive differential receive signals via the differential receive inputs and output amplified differential receive signals via the differential receive outputs; and a transformer comprising a primary winding and a secondary winding, the primary winding coupled with the differential transmit outputs of the power amplifier and the differential receive inputs of the low noise amplifier and the secondary winding coupled with the antenna. ## Claims ### Claim 1 A radio circuit, comprising: an antenna; a differential power amplifier, comprising differential transmit inputs and differential transmit outputs, configured to amplify differential transmit signals received via the differential transmit inputs and output the amplified differential transmit signals via the differential transmit outputs; a differential low noise amplifier, comprising differential receive inputs and differential receive outputs, configured to receive differential receive signals via the differential receive inputs and output amplified differential receive signals via the differential receive outputs; and a transformer comprising a primary winding and a secondary winding, the primary winding coupled at the same points with the differential transmit outputs of the power amplifier and the differential receive inputs of the low noise amplifier and the secondary winding coupled with the antenna, wherein the primary winding is center tapped. ### Claim 2 (depends on 1) The radio circuit of claim 1, further comprising a first adjustable capacitor connected across the primary winding, and a second adjustable capacitor coupled across the secondary winding. ### Claim 3 (depends on 1) The radio circuit of claim 1, wherein one side of the secondary winding is coupled with the antenna, and the other side is coupled to ground. ### Claim 4 (depends on 1) The radio circuit of claim 1, wherein the differential power amplifier comprises an output stage and a biasing stage. ### Claim 5 (depends on 1) The radio circuit of claim 1, wherein the center tap is coupled with a voltage derived from a power supply when signals are being transmitted via the power amplifier, and coupled to ground when signals are being received via the low noise amplifier. ### Claim 6 (depends on 1) The radio circuit of claim 1, wherein the differential low noise amplifier comprises an input stage and a biasing stage. ### Claim 7 A wireless communication device, comprising: an antenna; a digital circuit configured to generate digital transmit signals and process digital receive signals; a radio circuit, coupled with the digital circuit, the radio circuit comprising: a differential power amplifier, comprising differential transmit inputs and differential transmit outputs, configured to amplify differential transmit signals received via the differential transmit inputs and output the amplified differential transmit signals via the differential transmit outputs, a differential low noise amplifier, comprising differential receive inputs and differential receive outputs, configured to receive differential receive signals via the differential receive inputs and output amplified differential receive signals via the differential receive outputs, and a transformer comprising a primary winding and a secondary winding, the primary winding coupled with the differential transmit outputs of the power amplifier and the differential receive inputs of the low noise amplifier and the secondary winding coupled with the antenna, wherein the primary winding is center tapped. ### Claim 8 (depends on 7) The wireless communication device of claim 7, wherein the radio circuit further comprises a first adjustable capacitor connected across the primary winding, and a second adjustable capacitor coupled across the secondary winding. ### Claim 9 (depends on 7) The wireless communication device of claim 7, wherein one side of the secondary winding is coupled with the antenna, and the other side is coupled to ground. ### Claim 10 (depends on 7) The wireless communication device of claim 7, wherein the differential power amplifier comprises an output stage and a biasing stage. ### Claim 11 (depends on 7) The wireless communication device of claim 7, wherein the differential low noise amplifier comprises an input stage and a biasing stage. ### Claim 12 (depends on 7) The wireless communication device of claim 7, wherein the primary winding coupled at the same points with the differential transmit outputs of the power amplifier and the differential receive inputs of the low noise amplifier and the secondary winding coupled with the antenna. ### Claim 13 (depends on 7) The wireless communication device of claim 7, wherein the center tap is coupled with a voltage derived from a power supply when signals are being transmitted via the power amplifier, and coupled to ground when signals are being received via the low noise amplifier.