JPH04213905A - Planar array antenna - Google Patents

Abstract

PURPOSE:To reduce a feeder loss and to allow the antenna to trace a rocking of a traveling object by arranging a phase shifter at a position in a shortest distance from a microstrip batch antenna and selecting a beam direction of the antenna without moving the antenna itself. CONSTITUTION:A phase shifter is arranged to an upper face and a lower face of an antenna board 30, which changes a phase of radio wave signals from plural microstrip batch antennas 211-244. Each of the antennas 211-244 consists of two-layer boards 1, 6 and a ground plane 3 is formed between the two-layer boards 1 and 6. Moreover, lots of phase shifters with a different phase shift are connected in series. Thus, the beam direction is selected in plural directions without moving the antennas 211-244 themselves.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar array antenna, and more particularly to a planar array antenna in which a plurality of microstrip patch antennas are arranged on a substrate surface.

0002

2. Description of the Related Art In recent years, the field of use of satellite communication has expanded, and systems for performing satellite communication even on mobile bodies have been developed, but one of the problems that arises at this time is the antenna. Considering an automobile as a moving object, it is desired that the antenna be small, thin, and lightweight, and in this sense, a planar array antenna is suitable.

However, mobile systems require satellite tracking. Tracking can be achieved by tilting and rotating the entire antenna, but if the antenna is mounted on a rapidly moving object such as a car, a very high-speed servo mechanism, etc. is required. However, due to its weight, size, etc., it becomes impossible or expensive.

[0004] As an improvement measure, a plurality of microstrip patch antennas on the reference plane and a phase shifter installed in the middle of the microstrip line that is the feed line for the antennas that can form two excitation phases are used. A planar array antenna whose beam direction can be switched in two directions has been disclosed (Japanese Patent Application Laid-open No. 36202/1983).

[0005]

[Problem to be solved by the invention] However, when receiving weak radio waves such as satellite broadcasting, it is necessary to narrow down the antenna beam. It is not possible to follow the oscillations of

[0006] In contrast, if several stages of phase shifters with different excitation phase angles are connected in series, it is possible to follow the oscillation of a moving body, but if a large number of phase shifters are moved on the same plane (reference plane), If a phase shifter is formed, the area of the reference plane becomes larger, making the antenna larger, and the distance of the feeder line becomes longer because the phase shifter part has to be routed to the side of the antenna array, resulting in This results in a problem of increased losses.

SUMMARY OF THE INVENTION An object of the present invention is to provide a planar array antenna that reduces the feed line loss of an antenna having a phase shifter, is relatively small, and can follow the swinging motion of a moving body.

[0008]

[Means for Solving the Problems] The planar array antenna of the present invention is constructed from two layers of substrates (1, 6), and a ground plane (3) is formed between the two layers of substrates (1, 6). Substrate (30); Antenna array (40a, 40b, 40c, 40d);
A plurality of microstrip patch antennas (211 to 24
4); a phase shifter (101) for changing the phase of the radio signal;

In a preferred embodiment of the present invention, a large number of phase shifters (102, 103) each having a different amount of phase displacement are connected in series to the phase shifter (101).

Note that symbols in parentheses indicate corresponding elements in the embodiments shown in the drawings and described later.

[0011]

[Operation] According to this, the antenna array (40a, 40b, 40c, 40d) has a plurality of microstrip patch antennas (211 to 244) arranged at predetermined intervals.
and antenna rows (40a, 40b, 40c, 40d
) to connect multiple microstrip patch antennas (
A phase shifter (1) that changes the phase of the radio signal (211 to 244)
01) are arranged on the upper and lower surfaces of the antenna substrate (30), which is composed of two layers of substrates (1, 6) and forms a ground plane (3) between the two layers of substrates (1, 6). , multiple microstrip patch antennas (211-244
) By arranging the phase shifter (101) at the shortest distance from the feeder (101), it is possible to reduce the feed line loss. In addition, since the plurality of microstrip patch antennas (211 to 244) and the phase shifter (101) are not on the same plane, the antenna board (3
0) The area of the upper surface can be reduced, and as a result, the planar array antenna can be made smaller as a whole. In addition, multiple microstrip patch antennas (2
11 to 244) can reduce the influence of unnecessary radiation received from the phase shifter (101).

Furthermore, in a preferred embodiment of the present invention, a large number of phase shifters (102, 103) each having a different amount of phase displacement are connected in series to the phase shifter (101), so that a plurality of microstrip patch antennas can be used. (211-24
4) The beam direction can be switched to a plurality of directions without moving the plurality of microstrip patch antennas (211 to 244) themselves. Therefore, when the planar array antenna of the present invention is mounted on a moving object such as a car,
It is possible to follow the swinging motion of the moving body.

Other objects and features of the invention will become apparent from the following description of embodiments with reference to the drawings.

[0014]

[Embodiment] Fig. 1 shows a planar array antenna according to an embodiment of the present invention viewed from above, Fig. 2 shows a sectional view taken along line A-A in Fig. 1, and Fig. 3 shows a planar array antenna viewed from below. Each figure is shown as seen from above.

[0015] The BS antenna is originally only for reception, but
In the case of radio waves, transmission can be considered in the same way as reception, so here we will explain the transmission state. In FIG. 1, the antenna substrate 30 includes a two-layer dielectric substrate 1, a dielectric substrate 6, and a ground plate 3 formed between the dielectric substrate 1 and the dielectric substrate 6. On the top surface of the antenna board 30, there is an antenna consisting of a set of four microstrip patch antennas, which are radiating elements, arranged in a line horizontally (in the X-axis direction shown in FIG. 1) with a predetermined element spacing d apart. Row 40a
, 40b, 40c, and 40d are arranged vertically in four stages (in the Y direction shown in FIG. 1). That is, in this example, 16 microstrip patch antennas 2 mn (1≦m≦
4,1≦n≦4). This microstrip patch antenna 2mn is connected to pins 5a to 5d by microstrip lines 4a to 4d, which are feed lines, respectively. The pin 5a is guided from the top surface of the antenna board 30 to the bottom surface (back surface) of the antenna board 30, as shown in FIG. The same applies to pins 5b to 5d.

In FIG. 3, pins 5a to 5d guided to the bottom surface of an antenna board 30 are connected to a microphone strip line 20 via phase shifter arrays 10a to 10d. In this way, the antenna board 30 is composed of a two-layer board that forms a circuit consisting of a microstrip patch antenna 2mn on the top surface, a ground plate 3 on the middle surface, and phase shifter arrays 10a to 10d on the bottom surface of the antenna board 30. By this,
Phase shifter arrays 10a to 10 at the shortest distance from the antenna 2mm
d can be arranged, and as a result, the length of the feeder line is shortened, and the feeder line loss is reduced. Also, antenna 2m
Since n and the phase shifter arrays 10a to 10d are not on the same plane, the area of the top surface of the antenna board 30 can be reduced.
Moreover, the antenna 2mn can reduce the influence of unnecessary radiation received from the phase shifter arrays 10a to 10d. Also, antenna 2mn
The antenna density can also be increased compared to when the phase shifter arrays 10a to 10d are on the same plane.

FIG. 4 shows an enlarged view of the phase shifter array 10a shown in FIG. The phase shifter array 10a includes 101, 102, 103
It consists of a 3-bit phase shifter.

The phase shifter 101 includes a transformer 11 and a stub 12.
, a PIN diode 13, a DC block 14, and a bias line 15. The transformer 11 has a length λ
It consists of a g/4 microstrip line. In addition, λ
g indicates one wavelength on the microstrip line. A stub 12 consisting of a narrow portion 12a and a wide portion 12b is provided at both ends of the transformer 11, and a PIN diode 13 is provided at the tip of the narrow portion 12a. The other end of the PIN diode 13 is grounded. The bias line 15 consists of a narrow part 15a and a wide part 15b, both of which have a length of λg/4. The wide part 15b is a stub with an open end, and its base P (narrow part 15a and wide part 15
Since the connecting portion b) is in a short-circuited state in terms of high frequency, the impedance when looking at the narrow portion 15a from the main line 21 can be increased. Note that the DC block 14 prevents the bias current applied to the main line 21 from flowing out to other circuits.

When a bias voltage is applied to the base A, PI
N diode 13 performs on/off operation and both stubs 12
Short-circuit and release the tips of. In this state, the impedance of the stub 12 viewed from the transformer 11 is capacitive on one side and inductive on the other. That is, by switching and driving the PIN diode 13, two different excitation phase amounts can be obtained.

Next, the phase shifter 102 is composed of a hybrid coupler 16, a stub 17, a PIN diode 13, a DC block 14, and a bias line 15. In the hybrid coupler 16, the signal inputted from ■ is divided into ■ and ■ with equal power, and the phase of ■ is delayed by 90 degrees from the phase of ■. A stub 17 is provided at the tip of (1) and (2), and a PIN diode 13 is provided at the tip of the stub 17. If a bias voltage is applied here, the PIN diode
The lead 13 operates on/off to short-circuit and release the ends of both stubs 17. PIN by impedance Zs of stub 17
The impedance of the diode 13 is matched to the impedance Z0 of (1) and (2). In other words, the PIN diode 13
By switching and driving, two different phase amounts can be obtained.

[0021] The phase shifter 103 includes the phase shifter 102 and the stub 1.
The configuration is the same except for 8. Therefore, by changing the impedance Zs of the stub 18, two different phase amounts from the phase shifter 102 can be obtained.

[0022] From the above, 3 of 101, 102, 103
By switching and driving each PIN diode 13 of the bit phase shifter, eight different excitation phase amounts are obtained. Therefore, the microstrip patch antennas 211, 212, 21 connected by pin 5a
The maximum radiation direction of 3,214 is +θ (4
direction: +θ1, +θ2, +θ3, +θ4) and -θ in the opposite direction (4 directions: -θ1, -θ2, -θ3, -θ4),
It can be switched without moving the antenna itself. This also applies to the phase shifter arrays 10b, 10c, and 10d. Therefore, since the radiation direction of radio waves can be switched in eight directions, it is possible to relatively follow the swinging motion of a moving body such as an automobile. Furthermore, by connecting phase shifters with different excitation phase angles in series, highly accurate tracking becomes possible.

[0023]

As described above, according to the present invention, a plurality of microstrip patch antennas (
antenna array (40a, 40b) having antenna arrays (211 to 244);
, 40c, 40d) and antenna rows (40a, 40
A phase shifter (101) connected to microstrip patch antennas (b, 40c, 40d) and changing the phase of radio wave signals of a plurality of microstrip patch antennas (211 to 244) is constructed of a two-layer substrate (1, 6), The ground plane (3
), so the phase shifter (101
), the feed line loss can be reduced. Additionally, multiple microstrip patch antennas (21
1 to 244) and the phase shifter (101) are not on the same plane, the area of the upper surface of the antenna substrate (30) can be reduced, and as a result, the planar array antenna can be made smaller as a whole. Further, the plurality of microstrip patch antennas (211 to 244) are connected to a phase shifter (101
) can reduce the influence of unnecessary radiation received from

Furthermore, in a preferred embodiment of the present invention, a large number of phase shifters (102, 103) each having a different amount of phase displacement are connected in series to the phase shifter (101), so that a plurality of microstrip patch antennas can be used. (211-24
4) The beam direction can be switched to a plurality of directions without moving the plurality of microstrip patch antennas (211 to 244) themselves. Therefore, when the planar array antenna of the present invention is mounted on a moving object such as a car,
It is possible to follow the swinging motion of the moving body.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view showing a planar array antenna according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA shown in FIG. 1.

FIG. 3 is an external perspective view of the planar array antenna shown in FIG. 1, viewed upside down.

4 is an enlarged perspective view showing the phase shifter array 10a shown in FIG. 3. FIG.

[Explanation of symbols]

1: Dielectric substrates 211 to 244: Microstrip patch antenna (
Microstrip patch antenna) 3: Ground plate (ground plane) 4a to 4d: Microstrip line 5a
~5d: Pin 6: Dielectric substrate
10a to 10d: phase shifter rows 101 to 10
3: Phase shifter (phase shifter) 11: Transformer 12: Stub
13: PIN diode 14: DC block
15: Bias line 16: Hybrid coupler
17: Stub 18: Stub 20: Microstrip line
21: Main line 30: Antenna board (antenna board)

Claims (2)

[Claims] Claim: 1. An antenna substrate consisting of two layers of substrates and forming a ground plane between the two layers of substrates; a plurality of antenna substrates arranged at predetermined intervals in a direction perpendicular to the longitudinal direction of the top surface of the antenna substrate; A planar array comprising: an antenna row having microstrip patch antennas; and a phase shifter disposed on the lower surface of the antenna substrate, connected to the antenna row, and changing the phase of the radio wave signals of the plurality of microstrip patch antennas. antenna. 2. An antenna substrate consisting of a two-layer substrate, with a ground plane formed between the two layers; a plurality of microstrips arranged at predetermined intervals in a direction perpendicular to the longitudinal direction of the top surface of the antenna substrate; An antenna row having a patch antenna; a large number of phase shifters disposed on the lower surface of the antenna substrate and connected to the antenna row to change the phase of the radio wave signals of the plurality of microstrip patch antennas; and , a planar array antenna characterized in that the phase shift amounts of the plurality of phase shifters are different from each other.