Coupling reduction method for antennas in package
A Radio Frequency (RF) device may include a plurality of antennas and one or more conductive traces configured to trap a portion of energy transmitted from at least one of the plurality of antennas. The one or more conductive traces are sized and positioned such that undesired coupling between the plurality of antennas may be suppressed while maintaining performance parameters of at least one of the plurality of antennas. The plurality of antennas and the one or more conductive traces may be formed using a redistribution layer coupled to a chip embedded in a molding layer.
1. A Radio Frequency (RF) device, comprising:
first and second antennas formed in a redistribution layer of a package;
at least one conductive trace formed in the redistribution layer of the package, the at least one conductive trace separate from the first and second antennas, wherein the first antenna is a transmitter antenna, the second antenna is a receiver antenna, and the at least one conductive trace is sized and positioned to couple energy from the first antenna; and
first and second ground terminals.
2. The device of claim 1 , wherein both the first and second antennas are positioned on a same side of each of the at least one conductive trace.
3. The device of claim 1 , wherein the at least one conductive trace comprises first and second conductive traces, wherein the first conductive trace is connected to the first ground terminal and the second conductive trace is connected to the second ground terminal.
4. The device of claim 1 , wherein the RF device is tuned for a wavelength λ, the at least one conductive trace has an open end and an end connected to the first ground terminal, and a length between the open end and the end connected to the first ground terminal is substantially equal to an odd multiple of a quarter of the wavelength λ.
5. The device of claim 1 , wherein each of the first and second antennas comprises an antenna element and a feeder, and a distance between the antenna elements of the first and second antennas is greater than a distance between the feeders of the first and second antennas.
6. The device of claim 4 , wherein an isolation between the first and second antennas has a notch at a frequency corresponding to the wavelength λ.
7. The device of claim 6 , wherein a lowest point of the notch is less than −35 dB.
8. A Radio Frequency (RF) device, comprising:
a molding layer;
a chip embedded within the molding layer;
a redistribution layer coupled to the chip;
an antenna formed in the redistribution layer; and
a conductive trace formed in the redistribution layer, the conductive trace sized and positioned for trapping a portion of energy transmitted from the antenna.
9. The device of claim 8 , wherein the chip comprises a transmitter and/or a receiver.
10. The device of claim 8 , wherein the antenna comprises an antenna element and a feeder, the feeder has a first end connected to one of a group of terminals consisting of a ground terminal and a first output of the chip, a second end connected to a second output of the chip, and a third end connected to the antenna element, and the conductive trace comprises an open end and an end connected to the ground terminal.
11. The device of claim 10 , wherein the conductive trace is substantially parallel to the feeder.
12. The device of claim 10 , wherein the conductive trace is substantially perpendicular to the feeder.
13. The device of claim 8 , wherein the conductive trace comprises an open end and an end connected to a ground, the antenna is tuned for a wavelength λ, and a length between the open end of the conductive trace and the end connected to the ground is substantially equal to an odd multiple of a quarter of the wavelength.
14. The device of claim 8 , wherein:
the conductive trace is a first conductive trace,
the device comprises a plurality of conductive traces formed in the redistribution layer, each of the plurality of conductive traces comprises an open end and an end connected to a ground terminal, and
the plurality of conductive traces include the first conductive trace.
15. The device of claim 14 , wherein the first conductive trace has a first length selected to improve isolation performance in a first frequency range, and a second conductive trace of the plurality of conductive traces has a second length different from the first length, the second length being selected to improve isolation performance in a second frequency range different from the first frequency range.
16. The device of claim 10 , wherein:
the antenna is a first antenna,
the antenna element is a first antenna element,
the feeder is a first feeder,
the chip is a transmitting chip,
the ground terminal is a first ground terminal,
the device further comprises a second antenna formed in the redistribution layer,
the second antenna comprises a second antenna element and a second feeder, and
the feeder has a first end connected to one of a group of terminals consisting of a second ground terminal and a first output of a receiving chip, a second end connected to a second output of the receiving chip, and a third end connected to the second antenna element.
17. The device of claim 16 , wherein:
the device comprises a second conductive trace formed in the redistribution layer, and
the second conductive trace comprises an open end and an end connected to the second ground terminal.
18. The device of claim 17 , wherein a distance between the first and second conductive traces is greater than a distance between the first and second antenna elements.
19. The device of claim 8 , wherein the redistribution layer is metallic.