U.S. patent application number 09/985895 was filed with the patent office on 2002-05-30 for high-frequency circuit.
Invention is credited to Dohata, Hiroyuki.
Application Number | 20020063600 09/985895 |
Document ID | / |
Family ID | 18829238 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020063600 |
Kind Code |
A1 |
Dohata, Hiroyuki |
May 30, 2002 |
High-frequency circuit
Abstract
In a high-frequency circuit having bias lines that cross a
microstrip line in a plan view, portions of the bias lines are
formed on a reverse side of a substrate without forming, in the
microstrip line, capacitors required for separating the bias lines
from each other as an independent DC line, thus contributing to
miniaturizing the high-frequency circuit.
Inventors: |
Dohata, Hiroyuki; (Osaka,
JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
18829238 |
Appl. No.: |
09/985895 |
Filed: |
November 6, 2001 |
Current U.S.
Class: |
330/286 |
Current CPC
Class: |
H03F 3/68 20130101; H05K
3/4685 20130101; H05K 1/0237 20130101 |
Class at
Publication: |
330/286 |
International
Class: |
H03F 003/60 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2000 |
JP |
2000-357123 |
Claims
What is claimed is:
1. A high-frequency circuit comprising: a substrate having an
electronic component on an obverse side thereof; a microstrip line
formed on the obverse side of the substrate; one or more bias lines
connected to the electronic component on the obverse side of the
substrate and formed on a reverse side of the substrate so as to
cross the microstrip line in a plan view, wherein the bias lines
supply bias voltages to the electronic component.
2. A high-frequency circuit as claimed in claim 1, wherein, as the
bias line, a plurality of bias lines are formed so as to cross, in
a plan view, a single conductor formed as the microstrip line.
3. A high-frequency circuit as claimed in claim 2, wherein a
direction of current passing through any one of the bias lines is
opposite to a direction of current passing through the adjacent
bias line.
4. A high-frequency circuit as claimed in claim 2, wherein a filter
is connected to the bias lines.
5. A high-frequency circuit for use in a receiver converter,
comprising: a substrate; two microstrip lines formed on an obverse
side of the substrate; first electronic components built in one of
the microstrip lines; second electronic components built in the
other microstrip line; and a plurality of bias lines connected to
the first electronic components on the obverse side of the
substrate and formed continuously on the obverse side and a reverse
side of the substrate so as to cross, on the reverse side of the
substrate in a plan view, the microstrip line in which the second
electronic components are built, wherein the bias lines supply bias
voltages to the first electronic components.
6. A high-frequency circuit for use in a receiver converter as
claimed in claim 5, wherein portions of the bias lines are formed
on the reverse side of the substrate so as to cross, in a plan
view, a single conductor formed as one of the microstrip lines
which the second electronic components are built in.
7. A high-frequency circuit for use in a receiver converter as
claimed in claim 6, wherein a direction of current passing through
any one of the bias lines is opposite to a direction of current
passing through the adjacent bias line.
8. A high-frequency circuit for use in a receiver converter as
claimed in claim 6, wherein a filter is connected to the bias
lines.
9. A high-frequency circuit for use in a receiver converter as
claimed in claim 5, wherein the bias lines are formed continuously
with portions thereof lying on the obverse side and the reverse
side of the substrate connected together via through holes.
10. A high-frequency circuit for amplifying two differently
polarized waves, comprising: a substrate; a first microstrip line
formed on an obverse side of the substrate for transmitting a first
polarized wave; a second microstrip line formed on the obverse side
of the substrate for transmitting a second polarized wave; first
amplifiers built in the first microstrip line; second amplifiers
built in the second microstrip line; a plurality of first bias
lines connected to the first amplifiers on the obverse side of the
substrate for supplying bias voltages thereto and formed
continuously on the obverse side and a reverse side of the
substrate so as to cross, in a plan view, the second microstrip
line on the reverse side of the substrate; and a plurality of
second bias lines connected to the second amplifiers on the obverse
side of the substrate for supplying bias voltages thereto and
formed on the obverse side of the substrate so as not to cross, in
a plan view, the second microstrip line.
11. A high-frequency circuit for amplifying two differently
polarized waves as claimed in claim 10, wherein portions of the
first bias lines are formed on the reverse side of the substrate so
as to cross, in a plan view, a single conductor formed as the
second microstrip line.
12. A high-frequency circuit for amplifying two differently
polarized waves as claimed in claim 11, wherein a direction of
current passing through any one of the first and second bias lines
is opposite to a direction of current passing through the adjacent
bias line.
13. A high-frequency circuit for amplifying two differently
polarized waves as claimed in claim 11, wherein a filter is
connected to the first bias lines.
14. A high-frequency circuit for amplifying two differently
polarized waves as claimed in claim 10, wherein the first bias
lines are formed continuously with portions thereof lying on the
obverse side and the reverse side of the substrate connected
together via through holes.
15. A high-frequency circuit for use in a receiver converter,
comprising: a substrate having a conductor layer formed over almost
an entire reverse side thereof; a first microstrip line formed on
an obverse side of the substrate for transmitting a first signal
and segmented with a capacitor formed in between so that DC current
does not pass therethrough; a second microstrip line formed almost
parallel to the first microstrip line on the obverse side of the
substrate for transmitting a second signal and segmented with a
capacitor formed in between so that DC current does not pass
therethrough; first amplifiers built in the first microstrip line;
second amplifiers built in the second microstrip line; a plurality
of first bias lines having one end connected to the first
amplifiers on the obverse side of the substrate for supplying bias
voltages thereto and formed continuously on the obverse side and a
reverse side of the substrate so as to cross, in a plan view, the
second microstrip line on the reverse side of the substrate; and a
plurality of second bias lines having one end connected to the
second amplifiers on the obverse side of the substrate for
supplying bias voltages thereto and formed on the obverse side of
the substrate so as not to cross, in a plan view, the second
microstrip line, wherein other ends of the first and second bias
lines are located in a region on an opposite side of the second
microstrip line to the first microstrip line on the obverse side of
the substrate.
16. A high-frequency circuit for use in a receiver converter as
claimed in claim 15, wherein portions of the first bias lines are
formed on the reverse side of the substrate so as to cross, in a
plan view, a single conductor formed as the second microstrip
line.
17. A high-frequency circuit for use in a receiver converter as
claimed in claim 16, wherein a direction of current passing through
any one of the first and second bias lines is opposite to a
direction of current passing through the adjacent bias line.
18. A high-frequency circuit for use in a receiver converter as
claimed in claim 16, wherein a filter is connected to the first
bias lines.
19. A high-frequency circuit for use in a receiver converter as
claimed in claim 15, wherein the first bias lines are formed
continuously with portions thereof lying on the obverse side and
the reverse side of the substrate connected together via through
holes.
20. A microwave integrated circuit for use in a receiver converter,
comprising: a substrate having a conductor layer formed over almost
an entire reverse side thereof; a first microstrip line formed on
an obverse side of the substrate for transmitting a first signal
and segmented with a capacitor formed in between so that DC current
does not pass therethrough; a second microstrip line formed almost
parallel to the first microstrip line on the obverse side of the
substrate for transmitting a second signal and segmented with a
capacitor formed in between so that DC current does not pass
therethrough; first amplifiers comprising a GaAsFET, built in the
first microstrip line for amplifying the first signal; second
amplifiers comprising a GaAsFET, built in the second microstrip
line for amplifying the second signal; a plurality of first bias
lines formed continuously on the obverse and reverse sides of the
substrate, the first bias lines being formed continuously with
portions thereof lying on the obverse side and the reverse side of
the substrate connected together via through holes; having portions
thereof that cross the second microstrip line in a plan view, are
formed on the reverse side of the substrate; having one end thereof
connected to the first amplifiers on the obverse side of the
substrate; having the other end thereof located in a region on an
opposite side of the second microstrip line to the first microstrip
line on the obverse side of the substrate; and supplying bias
voltages to the first amplifiers, a plurality of second bias lines
formed continuously on the obverse side of the substrate, the
second bias lines having one end thereof connected to the second
amplifiers on the obverse side of the substrate; having the other
end thereof located in the same region as the other end of the
first bias lines; and supplying bias voltages to the second
amplifiers, a filter connected to the first bias lines.
21. A microwave integrated circuit for use in a receiver converter
as claimed in claim 20, wherein portions of the first bias lines
are formed on the reverse side of the substrate so as to cross, in
a plan view, a single conductor formed as the second microstrip
line, and a direction of current passing through any one of the
first and second bias lines is opposite to a direction of current
passing through the adjacent bias line.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a high-frequency circuit
for use in a low-noise high-frequency amplifier or the like of a
satellite broadcasting low-noise block down-converter. The present
invention, particularly, relates to a high-frequency circuit having
bias lines that cross a microstrip line in a plan view.
[0003] 2. Description of the Prior Art
[0004] A part of a low-noise high-frequency amplifier, used in an
LNB (Low-noise Block Down-converter) that receives a signal from a
broadcasting satellite or a communications satellite and outputs an
intermediate-frequency signal after frequency conversion, is shown
in FIG. 5 as an example of a conventional high-frequency circuit. A
low-noise high-frequency amplifier 10 of the LNB includes an MIC
(Microwave Integrated Circuit) comprising a substrate, microstrip
lines 14L and 14R formed thereon, and elements built in the
microstrip lines.
[0005] After received by an antenna (not illustrated),
radio-frequency signals in 12-GHz band in the form of a left-handed
polarized wave and a right-handed polarized wave are fed to the
microstrip lines 14L and 14R respectively through input terminals
11L and 11R thereof.
[0006] The input signal in the form of a left-handed polarized wave
fed through the input terminal 11L is outputted from an output
terminal 12L after having been amplified by two amplifiers 13L1 and
13L2, both of which are built in the microstrip line 14L. The input
signal in the form of a right-handed polarized wave fed through the
input terminal 11R is outputted from an output terminal 12R after
having been amplified by two amplifiers 13R1 and 13R2, both of
which are built in the microstrip line 14R.
[0007] Each of the amplifiers 13L1, 13L2, 13R1, and 13R2 comprises
a GaAsFET (Gallium Arsenide Field-Effect Transistor). Between the
amplifiers 13L1 and 13L2 in the microstrip line 14L is formed a
coupling capacitor CO so as to prevent DC (Direct Current) current
from passing therethrough.
[0008] The amplifiers 13L1 and 13L2 are designed to amplify a
signal fed to a gate G thereof and to output the signal from a
drain D when, for example, bias voltages -B1 and +B1 are applied to
the gate G and the drain D via bias lines 16L1 and 16L2
respectively. In this case, a source of the GaAsFET is connected to
ground (not illustrated).
[0009] Coupling capacitors C1 to C5 are formed in the microstrip
line 14R to separate the bias lines 16L1, 16L2, 16R1, and 16R2 from
each other as an independent DC line. The amplifiers 13R1 and 13R2
are designed to amplify a signal fed to the gate G thereof and to
output the signal from the drain D when, for example, bias voltages
-B2 and +B2 are applied to the gate G and the drain D respectively.
In this case, the source of the GaAsFET is connected to ground (not
illustrated).
[0010] However, according to the aforementioned low-noise
high-frequency amplifier 10, the microstrip lines 14L and 14R
formed on the substrate are made thin and, in addition, a width W
thereof is also made small so as to increase overall packaging
density. As a result, facing electrodes of each capacitor should be
made longer in the longitudinal direction of the microstrip line
14R so that each of the capacitors C1 to C5 gains a sufficient
facing area for having a specified capacitance.
[0011] The longer microstrip line 14R becomes, the more apart the
bias lines 16L1 and 16L2 are spaced out from each other.
Consequently, the overall length of the microstrip line 14L becomes
longer, resulting in an unduly larger low-noise high-frequency
amplifier 10 in size. A similar drawback is also seen even in the
case where the capacitors C1 to C5 can be formed without elongating
the facing electrodes thereof in the longitudinal direction of the
microstrip line 14R, because the gaps lying between the facing
electrodes of the capacitors are added up to an existing length
thereof.
[0012] Although it is not illustrated, in order to prevent the bias
lines from crossing one of the microstrip lines on an obverse side
of the substrate, the bias lines should be routed in two
directions, one from upper side and the other from lower side of
the substrate (FIG. 5). Accordingly, components mounted on the
substrate for supplying the bias voltage occupy at least two areas,
resulting in an unduly large circuit in size. If the bias lines are
routed parallel to the microstrip lines, the components for
supplying the bias voltage should be mounted at either left or
right side, or both (FIG. 5), resulting in an unduly long
high-frequency circuit in longitudinal direction. Therefore, it is
a common practice to design a high-frequency circuit having bias
lines that cross a microstrip line. As a result, not only such a
circuit as the aforementioned low-noise high-frequency amplifier 10
but also any high-frequency circuit having bias lines that cross a
microstrip line requires capacitors that separate each bias line as
an independent DC line, thereby making the high-frequency circuit
still unduly large in size.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide a
high-frequency circuit that can be made compact even in the case
where bias lines cross a microstrip line in a plan view.
[0014] To achieve the above object, according to one aspect of the
present invention, a high-frequency circuit comprises a substrate
having an electronic component on an obverse side thereof, a
microstrip line formed on the obverse side of the substrate, and
one or more bias lines connected to the electronic component on the
obverse side of the substrate and formed on a reverse side of the
substrate so as to cross the microstrip line in a plan view,
wherein the bias lines supply bias voltages to the electronic
component.
[0015] In this structure, the bias line lying on the reverse side
of the substrate and crossing the microstrip line in a plan view,
is insulated therefrom and supplies bias voltages to the electronic
component.
[0016] According to another aspect of the present invention, in a
high-frequency circuit as described above, as the bias line, a
plurality of bias lines are formed so as to cross, in a plan view,
a single conductor formed as the microstrip line.
[0017] According to still another aspect of the present invention,
in a high-frequency circuit as described above, a direction of
current passing through any one of the bias lines is opposite to a
direction of current passing through the adjacent bias line.
[0018] According to still another aspect of the present invention,
in a high-frequency circuit as described above, a filter is
connected to the bias lines.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] This and other objects and features of the present invention
will become clear from the following description, taken in
conjunction with the preferred embodiments with reference to the
accompanying drawings in which:
[0020] FIG. 1 is a schematic diagram showing an LNB having a
low-noise high-frequency amplifier of a first embodiment of the
invention;
[0021] FIG. 2 is a schematic diagram showing the low-noise
high-frequency amplifier of the first embodiment;
[0022] FIG. 3 is a diagram showing a cross section of A-A shown in
FIG. 2;
[0023] FIG. 4 is a schematic diagram showing a low-noise
high-frequency amplifier of a second embodiment; and
[0024] FIG. 5 is a schematic diagram showing a conventional
low-noise high-frequency amplifier.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Hereinafter, embodiments of the present invention will be
described with reference to the accompanying drawings. In FIGS. 1
to 4, such components as are found also in FIG. 5 are identified
with the same reference numerals.
[0026] FIG. 1 is a schematic diagram showing an LNB (low-noise
block down-converter) having a low-noise high-frequency amplifier
of a first embodiment. An LNB 1 comprises a feeder horn 9, a
low-noise high-frequency amplifier 10, band-pass filters 3L and 3R,
mixers 4L and 4R, a local oscillator 5, a first
intermediate-frequency amplifier 6, and a controller 8.
Radio-frequency signals in 12.2-GHz to 12.7-GHz band consisting of
a left-handed polarized wave and a right-handed polarized wave are
received by the feeder horn 9 and amplified respectively by the
low-noise high-frequency amplifier 10.
[0027] The amplified signals are fed to the mixers 4L and 4R
through the band-pass filters 3L and 3R that allow signals of
specific frequencies to pass through. The mixers 4L and 4R convert
the signals into IF (Intermediate Frequency) signals of frequencies
ranging from 950 MHz to 1,450 MHz based on a local frequency of
11.25 GHz generated by the local oscillator 5.
[0028] A switch block 6a in the first intermediate-frequency
amplifier 6 is controlled by the controller 8 and selects the IF
signals of the left-handed polarized wave or the right-handed
polarized wave. An amplifier 6b in the first intermediate-frequency
amplifier 6 amplifies the IF signals selected by a switch circuit
6d. An amplifier 6c amplifies the IF signals selected by a switch
circuit 6e. The amplified signals are then outputted to output
terminals 7a and 7b after passing through coupling capacitors C7
and C8 respectively.
[0029] The output terminals 7a and 7b receive DC voltage from a
tuner circuit (not illustrated) respectively. One ends of choke
coils L1 and L2 are connected to the output terminals 7a and 7b
respectively and the other ends to anodes of diodes D1 and D2
respectively. Cathodes of the diodes D1 and D2 are connected to the
controller 8. The controller 8, according to the DC voltage
supplied thereto, supplies power to the low-noise high-frequency
amplifier 10, the local oscillator 5, and the first
intermediate-frequency amplifier 6 via bias lines 16, 21, and 22
respectively.
[0030] FIG. 2 is a schematic diagram showing the low-noise
high-frequency amplifier. After received by the feeder horn (FIG.
1), 12-GHz band radio frequency signals in the form of a
left-handed polarized wave and a right-handed polarized wave are
fed to microstrip lines 14L and 14R respectively via input
terminals 11L and 1 IR thereof.
[0031] The input signal in the form of a left-handed polarized wave
that is fed through the input terminal 11L is outputted from an
output terminal 12L after having been amplified by two amplifiers
13L1 and 13L2 built in the microstrip line 14L. The input signal in
the form of a right-handed polarized wave that is fed through the
input terminal 11R is outputted from an output terminal 12R after
having been amplified by two amplifiers 13R1 and 13R2 built in the
microstrip line 14R.
[0032] Each of the amplifiers 13L1, 13L2, 13R1, and 13R2 comprises
a GaAsFET (Gallium Arsenide Field-Effect Transistor). Between the
amplifiers 13L1 and 13L2 in the microstrip line 14L is formed a
coupling capacitor CO so that DC current does not pass
therethrough. At the same time, between the amplifiers 13R1 and
13R2 in the microstrip line 14R is formed a coupling capacitor C3
so that DC current does not pass therethrough.
[0033] The amplifiers 13R1 and 13R2 are designed to amplify a
signal fed to a gate G thereof and to output the signal from a
drain D when, for example, bias voltages -B2 and +B2 are applied to
the gate G and the drain D via bias lines 16R1 and 16R2
respectively. In this case, a source of the GaAsFET is connected to
ground (not illustrated).
[0034] The bias lines 16L1 and 16L2 are configured to cross the
microstrip line 14R in a plan view. FIG. 3 is a diagram showing a
cross section of A-A shown in FIG. 2. The microstrip line 14R is
formed on an obverse side of a substrate 20. On the obverse side of
the substrate 20 are formed the bias lines 16L1 and 16L2 whose
portions are also formed on a reverse side of the substrate 20 so
as to cross the microstrip line 14R in a plan view. The bias lines
16L1 and 16L2 formed on the obverse side of the substrate are
connected continuously to the portions thereof formed on the
reverse side of the substrate 20 via through holes 17
respectively.
[0035] In this configuration, the amplifiers 13L1 and 13L2 amplify
a signal fed to the gate G thereof and output the signal from the
drain D when, for example, bias voltages -B1 and +B1 are applied to
the gate G and the drain D via the bias lines 16L1 and 16L2
respectively.
[0036] In FIG. 3, a numeral 18 is a conductor layer formed over
almost an entire reverse side of the substrate 20. However, it
should be noted that the conductor layer is not formed to cover the
bias lines 16L1 and 16L2 and edges thereof that are formed on the
reverse side of the substrate 20.
[0037] In this embodiment, contrary to a conventional circuit as
shown in FIG. 5, it is not required to form capacitors C1, C2, C4,
and C5 by segmenting the microstrip line 14R so as to separate each
bias line from each other as an independent DC line even in the
case where the bias lines 16L1 and 16L2 are arranged to cross the
microstrip line 14R in a plan view.
[0038] The microstrip line 14R thus can be shortened, making it
also possible to shorten the overall length of the microstrip line
14L because the distance between the bias lines 16L1 and 16L2
becomes smaller. This contributes to miniaturizing the low-noise
high-frequency amplifier 10 comprising an MIC.
[0039] FIG. 4 is a schematic diagram showing a low-noise
high-frequency amplifier of a second embodiment. A low-noise
high-frequency amplifier 10 in this embodiment functions in the
same manner as that in the first embodiment as shown in FIG. 2 as
previously described. Amplifiers 13L1 and 13L2 built in a
microstrip line 14L receive bias voltages through bias lines 16L1
and 16L2.
[0040] The bias lines 16L1 and 16L2 are connected to a reverse side
of a substrate 20 (FIG. 3) via through holes 17 as is the case in
the first embodiment. In this case, four bias lines 16L1 and 16L2
cross, in a plan view, a single conductor 14a formed as a
microstrip line 14R. In this arrangement, it is possible to secure
a wide area H on the obverse side of the substrate as shown in FIG.
4. As a result, it is possible to mount other electronic components
in this area H, contributing to realizing high-density packaging of
the low-noise high-frequency amplifier 10. It is to be noted that
portions of the bias lines 16L1 and 16L2 are laid in an oblique
angle so that the bias lines will be equal in length.
[0041] As shown by arrows and numerals I1 to I4 in FIG. 4, a
direction of current passing through any one of the bias lines 16L1
and 16L2 is opposite to a direction of current passing through the
adjacent bias line. In this arrangement, magnetic fields generated
by the currents I1 to I4 passing through the bias lines 16L1 and
16L2 cancel each other, resulting in a reduction in the magnetic
fields affecting the microstrip line 14R.
[0042] Another adverse effect that may influence other circuits is
caused by signals being transferred from the microstrip line 14R to
the bias lines 16L1 and 16L2 formed on the reverse side of the
substrate 20. To overcome this, filters 24 including coils L3 and
L4, and capacitors C9 and 10 are connected to the bias lines 16L1
and 16L2 respectively so as to remove the transferred signals and
alleviate the adverse effect that will otherwise influence the
other circuits.
[0043] Although the first and second embodiments deal with a
low-noise high-frequency amplifier for use in an LNB, for achieving
similar effects, the present invention is applicable also to
high-frequency circuits having a circuit layout in which bias lines
cross microstrip lines.
[0044] According to the present invention, in the case where bias
lines are arranged to cross a microstrip line in a plan view,
coupling capacitors to segment the microstrip line for separating
each bias line as an independent DC line are not required as in the
conventional case if portions of the bias lines are formed on a
reverse side of a substrate. Consequently, the mictostrip line can
be made so shorter that the bias lines can be arranged closer to
each other, contributing to miniaturizing a high-frequency
circuit.
[0045] Moreover, according to the present invention, distances
between the bias lines can be made smaller because a plurality of
bias lines are formed so as to cross, in a plan view, a single
conductor formed as a microstrip line. In this arrangement, a wide
area for mounting other electronic components can be secured in the
high-frequency circuit for realizing a high-density packaging of
high-frequency circuits.
[0046] Furthermore, according to the present invention, a direction
of current passing through any one of the bias lines is opposite to
a direction of current passing through the adjacent bias line. In
this arrangement, magnetic fields generated by the currents passing
through the bias lines cancel each other, resulting in a reduction
in the magnetic fields affecting the microstrip lines.
[0047] Moreover, according to the present invention, an adverse
effect, that may otherwise influence other circuits and is caused
by signals being transferred from the microstrip lines to the bias
lines formed on the reverse side of the substrate, is reduced by
connecting filters to the bias lines.
* * * * *