JP2000114858A - Slot power feeder microstrip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a transmission loss caused by a microstrip line. SOLUTION: A laminate structure is provided by overlapping a first dielectric substrate 1a having an antenna pattern (patch) 7 and a second dielectric substrate 1b having a ground conductor 3, a slot 2, a first microstrip line 4a, a second microstrip line 4b and a low noise amplifier 5 or the like. In this case, the first microstrip line 4a having neatly the length of/4 is provided almost vertically to the slot 2, the low noise amplifier 5 is provided on the opposite side of the first microstrip line 4a with the slot 2 in between, and a signal input lead wire 5a of the low noise amplifier 5 is connected to the first microstrip line 4a almost orthogonally to the slot 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a slot-fed microstrip antenna used for receiving BS, CS, and the like.

[0002]

2. Description of the Related Art FIGS. 2A and 2B are an enlarged longitudinal sectional view (A) and an enlarged plan view (B) of a main part of a conventional slot-fed microstrip antenna. In this antenna, a first dielectric substrate 1a having an antenna pattern (patch) 7 is superimposed on a second dielectric substrate 1b having a slot 2, a ground conductor 3, a microstrip line 4, a low noise amplifier 5, and the like. It has a laminated structure.

For example, a primary radiator installed at the focal point of a parabolic antenna (not shown) captures radio waves, and an LNB (Low Noise Block) integrally formed with the primary radiator.
The antenna pattern 7 received in the antenna pattern 7 receives a radio wave, and the signal of the radio wave is transmitted through the slot 2 coupled to the antenna pattern 7 and further transmitted through the microstrip line 4 coupled to the slot 2. Low noise amplifier, for example, HEMT (High Electron Mobility Trans
istor) 5 or the like, and the signal is amplified by the HEMT 5 with low noise. Note that the description of the circuits after the HEMT 5 in the LNB is irrelevant to the present technology, and thus will be omitted.

However, conventionally, slot 2 and HEMT5
, A predetermined transmission loss occurs when transmitting a signal through the microstrip line 4, the signal power (C) supplied to the HEMT 5 is reduced, and the ratio value (C / N) to the noise power (N) is thus reduced. Therefore, there is a problem that the noise figure (NF) in the low noise amplifier is deteriorated.

In general, since the characteristic impedance of the microstrip line 4, for example, 50Ω, and the input impedance of a low-noise amplifier, for example, HEMT5, are different, it is necessary to match both impedances.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a slot-fed type microstrip antenna which reduces transmission loss caused by a microstrip line and facilitates impedance matching. The purpose is to:

[0007]

In order to achieve the above object, a first dielectric substrate having an antenna pattern (patch), a slot, a ground conductor, a first microstrip line, a second microstrip line, and a low noise A slot-fed microstrip antenna comprising a second dielectric substrate having an amplifier and the like, wherein a first microstrip line provided on one side of the slot in a direction substantially perpendicular to the slot, and a signal input lead wire is connected to the slot. A low-noise amplifier provided on the other side of the slot connected to the first microphone strip line substantially orthogonal to the second microstrip line provided on the other side of the slot connected to the signal output lead of the low-noise amplifier. .

Further, the low noise amplifier is constituted by a HEMT.

Further, the end of the first microstrip line is opened and its length is set to an odd multiple of approximately λ / 4, where λ is the wavelength of the radio wave used.

[0010] Further, the odd multiple is set to one.

The end of the first microstrip line is grounded, and its length is substantially a positive integer multiple of λ / 2, where λ is the wavelength of the radio wave used.

Further, the above-mentioned slot is configured to be a rectangular slot.

The position where the signal input lead wire of the low-noise amplifier is substantially perpendicular to the slot is set at a position other than the center of the slot.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, a slot-fed microstrip antenna according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is an enlarged longitudinal sectional view (a) of an essential part of an embodiment of a slot-fed microstrip antenna according to the present invention, an enlarged plan view (b) of an essential part, and an enlarged plan view (c) of an essential part of another embodiment. It is a principal part enlarged plan view (d) of another Example. The slot-fed microstrip antenna according to the present invention is formed by cutting a first dielectric substrate 1a having an antenna pattern (patch) 7, a ground conductor 3, and a conductor at a position corresponding to the ground conductor 3 into, for example, a rectangular shape. Slot 2, a first microstrip line 4a having an open end provided on one side of the slot 2, a second microstrip line 4b provided on the other side of the slot 2, a second dielectric strip having a low noise amplifier 5, and the like. When λ is the wavelength of the radio wave used, the first microstrip line 4a having a length of approximately λ / 4 is connected to the slot 2 in a direction substantially perpendicular to the slot 2. , And the low-noise amplifier 5 is provided on the other side of the slot 2, and a signal input lead wire of the low-noise amplifier 5 is provided.
5a was connected to the first microstrip line 4a substantially orthogonal to the slot 2, and a signal output lead was connected to the second microstrip line 4b.

The slot-fed microstrip antenna according to the present invention includes a low-noise amplifier 5, for example, a HEMT.
Since the signal input lead wire 5a (High Electron Mobility Transistor) and the slot 2 are arranged so as to intersect in a substantially orthogonal state, a signal passing through the slot 2 can be directly coupled to the lead wire 5a. In other words, the combined signal does not pass through the microstrip line 4 (FIG. 2) but is transmitted directly to the HEMT 5 only through the signal input lead 5a. Accordingly, since the combined signal can be amplified with low noise by the HEMT 5 with almost no transmission loss, the noise figure (N
F) can be prevented from deteriorating.

Since the end of the first microstrip line 4a is set in an open state, when λ is the wavelength of the radio wave used, the direction of the electric field is switched at a position almost an odd multiple of λ / 4. The antenna pattern (patch) 7 and the signal input lead 5a of the low-noise amplifier 5 are most efficiently coupled via the slot 2 provided at this position.
Therefore, approximately λ / 4, 3 × λ / 4, 5 × λ / 4,...
The optimum coupling state can be obtained at such positions.

Further, another embodiment will be described. As shown in FIG. 1 (d), the end of the first microstrip line 4a is
The ground conductor 3 provided on the other surface of the second dielectric substrate 1b (FIG. 1)
In the case of (b), the direction of the electric field is switched at a position substantially equal to a positive integer multiple of λ / 2, and if the slot 2 is provided at this position, the antenna pattern (patch) 7 and the low The signal input lead 5a of the noise amplifier 5 is most efficiently coupled. Therefore, approximately λ / 2, λ, 3 × λ
..,...

Another embodiment will be described. FIG.
As shown in (c), the position where the signal input lead wire 5a of the low-noise amplifier 5 is substantially orthogonal to the slot 2 is moved from the center of the slot 2 to the end and positioned so as to be the optimum position. Thereby, the matching between the characteristic impedance of the first microstrip line 4a and the input impedance of the HEMT 5 or the like can be easily brought to the best state.

[0019]

As described above, the present invention provides a slot-fed microstrip antenna that reduces transmission loss caused by a microstrip line and facilitates impedance matching. Therefore, HEM
The present invention, configured to couple directly to the T5 lead,
When a signal is transmitted through the microstrip line 4 between the slot 2 and the HEMT 5, a predetermined transmission loss occurs, so that the noise figure (NF) in the low-noise amplifier is degraded. There are merits that can be done.

Further, since the length of the first microstrip line 4a can be made as small as λ / 4 in the shortest state, this is an effective technique for miniaturizing the antenna.

Further, the first microstrip line 4a
And the input impedance of the HEMT5 and the like had to be matched,
The present invention relates to a microstrip line,
The position where the signal input lead wire 5a of T5 is substantially orthogonal to the slot 2 is moved from the center of the slot 2 to the end and positioned so as to be an optimum position, so that the characteristic impedance of the first microstrip line 4a is reduced. , HEMT
Matching with an input impedance such as 5 can be easily made the best state.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional view of a main part of an embodiment of a slot-fed microstrip antenna according to the present invention (a), an enlarged plan view of a main part (b), and an enlarged plan view of a main part of another embodiment (c).
It is a principal part enlarged plan view (d) of another Example.

FIGS. 2A and 2B are an enlarged longitudinal sectional view (A) and an enlarged plan view (B) of a main part of a conventional slot-fed microstrip antenna.

[Explanation of symbols]

 1a First dielectric substrate 1b Second dielectric substrate 2 Slot 3 Ground conductor 4 Microstrip line 4a First microstrip line 4b Second microstrip line 5 Low noise amplifier (HEMT) 5a Signal input lead 6 Through hole 7 Antenna Pattern (patch)

Claims (7)

[Claims] 1. A semiconductor device comprising: a first dielectric substrate having an antenna pattern (patch); and a second dielectric substrate having a slot, a ground conductor, a first microstrip line, a second microstrip line, a low noise amplifier, and the like. A first microstrip line provided on one side of the slot in a direction substantially perpendicular to the slot, and a signal input lead wire connected to the first microphone strip line substantially orthogonal to the slot. And a second microstrip line provided on the other side of the slot to which the signal output lead wire of the low noise amplifier is connected. 2. The low noise amplifier according to claim 1, wherein the low noise amplifier is a HEMT (High E
2. A slot-fed microstrip antenna according to claim 1, wherein the slot-fed microstrip antenna is constituted by an electron mobility transistor. 3. The slot feeding type according to claim 1, wherein an end of said first microphone strip line is opened and its length is an odd multiple of approximately λ / 4, where λ is the wavelength of a radio wave used. Microstrip antenna. 4. The slot-fed microstrip antenna according to claim 3, wherein the odd multiple is set to one. 5. The slot according to claim 1, wherein an end of the first microphone strip line is grounded, and a length thereof is substantially a positive integer multiple of λ / 2, where λ is a wavelength of a radio wave used. Feed type microstrip antenna. 6. The slot-fed microstrip antenna according to claim 1, wherein said slot is a rectangular slot. 7. The slot-fed microstrip antenna according to claim 1, wherein the position where the signal input lead wire of the low noise amplifier is substantially orthogonal to the slot is other than the center of the slot.