RF transceiver adapted for signal isolators and proximity sensors
View Patent ↗A transceiver having a transmitting antenna, a receiving antenna, and a substrate having transmitter and receiver dies is disclosed. The transmitter generates an RF signal having a carrier frequency and the receiver detects and amplifies signals of the carrier frequency. The transmitting antenna and/or the receiving antenna includes a first wire antenna loop having a length greater than or equal to one tenth of a wavelength of the carrier frequency. The first wire antenna loop is connected to the transmitter die by a wire bond on a bond pad of the transmitter die. The antenna loop or loops can be encapsulated in an insulating material to protect the loops and fix the loops in space. The transceiver can be configured to operate as a galvanic isolator or a proximity detector.
1. A transceiver, comprising:
a radio-frequency transmitter assembly, comprising:
a first substrate;
a first die comprising a radio-frequency transmitter circuit, the first die mounted on a major surface of the first substrate;
a first antenna connected to the radio-frequency transmitter circuit, the first antenna comprising at least one wire segment with segment ends attached to respective bonding pads located on the major surface of the first substrate; and
a first power supply circuit configured to provide power to the radio-frequency transmitter circuit; and
a radio-frequency receiver assembly, comprising:
a second substrate;
a second die comprising a radio-frequency receiver circuit, the second die mounted on a major surface of the second substrate;
a second antenna connected to the radio-frequency receiver circuit, the second antenna comprising at least one wire segment with segment ends attached to respective bonding pads located on the major surface of the second substrate; and
a second power supply circuit configured to provide power to the radio-frequency receiver circuit;
wherein the radio-frequency transmitter assembly and the radio-frequency receiver assembly are attached to each other such that the major surface of the first substrate faces the major surface of the second substrate with an insulating barrier located in between, the insulating barrier arranged to provide voltage and noise isolation between the radio-frequency transmitter and receiver circuits, while accommodating radio-frequency coupling between the first and second antennae.
2. The transceiver of claim 1 , wherein
said transmitter circuit is configured for generating a signal having a carrier frequency and said receiver circuit is configured for detecting and amplifying signals of said carrier frequency, and wherein said first antenna and said second antenna each has a length substantially equal to one tenth of a wavelength of said carrier frequency.
3. The transceiver of claim 2 wherein said first antenna and said second antenna are separated by a distance less than 3 wavelengths of said carrier frequency.
4. The transceiver of claim 1 wherein said first and second antennae each comprises a first end that is wire bonded to a conductor on said first and second substrates respectively.
5. The transceiver of claim 1 wherein said first and second antennae each comprises a second end that is wire bonded to a conductor on said first and second dies respectively.
6. The transceiver of claim 1 wherein said first and second antennae each comprises a second end that is wire bonded to a conductor on said first and second substrates respectively.
7. The transceiver of claim 1 wherein said first and second antennae comprise dipoles.
8. The transceiver of claim 1 wherein said first and second antennae each comprises a closed loop having a plane parallel to a surface of said first and second substrates respectively.
9. The transceiver of claim 1 , further comprising:
a first insulating layer that encapsulates the first die, the first antenna, the major surface of the first substrate, and at least a portion of the first power supply circuit; and
a second insulating layer that encapsulates the second die, the second antenna, the major surface of the second substrate, and at least a portion of the second power supply circuit;
and wherein the insulating barrier incorporates a bond between an external surface of the first insulating layer and an external surface of the second insulating layer.
10. The transceiver of claim 1 wherein the transceiver forms a part of a galvanic isolator.
11. A transceiver, comprising:
a radio-frequency transmitter comprising:
a first substrate;
a first die comprising a radio-frequency transmitter circuit, the first die mounted on a major surface of the first substrate;
a first antenna connected to the radio-frequency transmitter circuit, the first antenna comprising at least one wire segment with segment ends attached to respective bonding pads located on the major surface of the first substrate, the first antenna operable to emit a radio-frequency signal in an upwards direction with reference to a top surface of the first substrate; and
a first connector for providing connections to the radio-frequency transmitter, the first connector located on a bottom surface of the first substrate and facing away from the direction of emission of the radio-frequency signal;
a radio-frequency receiver, comprising:
a second substrate;
a second die comprising a radio-frequency receiver circuit, the second die mounted on a major surface of the second substrate;
a second connector for providing connections to the radio-frequency receiver, the second connector located on the bottom surface of the second substrate; and
a second antenna connected to the radio-frequency receiver circuit, the second antenna comprising at least one wire segment with segment ends attached to respective bonding pads located on the major surface of the second substrate;
a shield located between said radio-frequency transmitter and receiver, said shield arranged to prevent a signal that is emitted by said first antenna from being directly received in said second antenna, while permitting said signal to be received in said second antenna after reflection from an object located external to the transceiver; and
an insulating layer located between the radio-frequency transmitter and the radio-frequency receiver to provide voltage and noise isolation between the radio-frequency transmitter and receiver circuits, and
wherein the first and the second antennae are oriented such that said signal is reflected by said object only when said object is located within a desired range for proximity detection.
12. The transceiver of claim 11 wherein the substrate is part of a printed circuit board.
13. The transceiver of claim 11 wherein said first and second antennae each comprises a first end that is wire bonded to a conductor on said substrate.
14. A method of operating a radio-frequency transceiver assembly, the method comprising:
transmitting a ranging signal from a radio-frequency transmitter circuit that is co-located with a radio-frequency receiver circuit on a major surface of a substrate of the radio-frequency transceiver assembly, the ranging signal selected to have a signal strength adapted for proximity detection;
providing an insulating layer between the radio-frequency transmitter and receiver circuits for voltage and noise insulation;
providing power and signal connections to said radio-frequency transmitter circuit through a first connector located on an opposing major surface of the substrate;
providing power and signal connections to said radio-frequency receiver circuit through a second connector located on said opposing major surface of the substrate;
preventing said ranging signal from being directly received in said receiver circuit, while permitting said ranging signal to be received in said receiver circuit after reflection from an object located external to the radio-frequency transceiver assembly; and
using said ranging signal received in said radio-frequency receiver circuit to detect proximity of said object to said radio-frequency transceiver assembly.
15. The method of claim 14 , wherein preventing said ranging signal from being directly received in receiver circuit comprises placing a shield between radio-frequency transmitter circuit and radio-frequency receiver circuit.