Directional coupler
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorIgor Spokoinyi
Life of this patent
Estimating the term…
Abstract
Microstrip directional couplers and methods of their design are disclosed. According to one aspect, a microstrip directional coupler has a substrate of a first thickness. Disposed upon the substrate is a first microstrip having a first portion of a first length and a second microstrip having a second portion of a second length. The first and second microstrips are positioned to exhibit a gap between the first portion and the second portion. The first and second lengths are less than one sixteenth of a wavelength at the lowest frequency of operation of the directional coupler. The gap is less than a predetermined amount to reduce a difference in phase velocity of even and odd modes of the microstrip directional coupler.
Claims22
A micro-strip directional coupler, the micro-strip directional coupler comprising:
- a substrate having a first thickness;
- and
- disposed upon the substrate:
- a first micro-strip in air having a first portion of a first length;
- and
- a second micro-strip in air having a second portion of a second length directed parallel to the first portion, the first and second micro-strips being positioned to exhibit a first gap between the first portion and the second portion, the first and second lengths being less than one-sixteenth of a wavelength in air at a lowest frequency of operation of the directional coupler, the first gap being less than a predetermined amount to reduce a difference in phase velocity of even and odd order modes of the directional coupler.
A radio frequency, RF, output circuit comprising:
- a power amplifier;
- an antenna feed;
- and
- a directional coupler electrically disposed between the power amplifier and the antenna, the directional coupler having a first port connected to the power amplifier, a second port connected to the antenna, a third port, and a fourth port, the directional coupler further including:
- a first micro-strip in air having a first portion of a first length;
- and
- a second micro-strip in air having a second portion of a second length, the first micro-strip and the second micro-strip positioned in parallel with a gap between the first micro-strip and the second micro-strip, the first and second lengths being less than one-sixteenth of a wavelength in air at a lowest frequency of operation of the directional coupler and the gap being less than a predetermined amount so that the directional coupler exhibits a coupling of the first and second micro-strips that exceeds substantially 20 decibels, dB, and a directivity that exceeds substantially 20 dB, at the lowest frequency of operation of the directional coupler.
A method of designing a directional coupler, the method comprising:
- choosing a substrate having a thickness and a dielectric constant;
- and
- etching the substrate to form parallel micro-strips in air having a first length, with a gap between the parallel micro-strips, the first length chosen to be less than substantially one-sixteenth of a wavelength in air at a lowest frequency of operation of the directional coupler, the gap being less than a predetermined amount to reduce a difference in phase velocity of even and odd order modes of the directional coupler.
Dependencies are inferred from the claim text.