JP2004088508A - High frequency module with antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency antenna module for suppressing the increase of the whole area of the module itself, mounting circuit components on a GND face and allowed to be manufactured by simple manufacturing processes. <P>SOLUTION: The high frequency antenna module comprises an RF substrate on which RF components constituting an RF circuit is mounted, a radiation element of an antenna which is faced to the RF substrate, GND which is one face of the RF substrate, arranged on the radiation element side and constitutes the GND face of the antenna, and space formed between the radiation element and the GND. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-frequency module with an antenna used for mobile communication and a local area network.
[0002]
[Prior art]
As a first conventional example of a high-frequency antenna module, JP-A-11-234033 discloses a structure in which a patch antenna and a high-frequency circuit are arranged side by side and integrated.
[0003]
Further, as a second conventional example of a high-frequency antenna module, a structure in which an antenna and a high-frequency switch circuit are integrated and a helical antenna is formed inside a high-frequency switch circuit board is disclosed in Japanese Patent Application Laid-Open No. 2001-189677. .
[0004]
Further, as a third conventional example of a high-frequency antenna module, Japanese Patent Application Laid-Open No. 2002-135041 discloses a structure in which a plurality of patch antennas and an RF circuit are integrated and an RF circuit is formed on the back surface of the patch antenna. .
[0005]
[Problems to be solved by the invention]
In the first conventional example, since the patch antenna and the high-frequency circuit are arranged side by side and integrated, there is a problem that the entire area of the high-frequency antenna module becomes large.
[0006]
In the second conventional example, a helical antenna is used, and since the characteristics of the antenna are greatly affected by GND, there is a problem that circuit components cannot be mounted on the GND surface.
[0007]
Further, in the third conventional example, a plurality of patch antennas and an RF circuit are integrated, and an RF circuit is formed on the back surface of the patch antenna. There is a problem that it becomes complicated and costly.
[0008]
An object of the present invention is to provide a high-frequency antenna module in which the entire area of the high-frequency antenna module is not increased, circuit components can be mounted on the GND surface, and the manufacturing process of the high-frequency antenna module is simple. It is the purpose.
[0009]
[Means for Solving the Problems]
The present invention provides an RF board on which an RF component constituting an RF circuit is mounted, and is provided on a side opposite to the side on which the RF component is mounted as viewed from the RF board, and faces the RF board. A radiating element of the antenna and a GND provided on the radiating element side on one surface of the RF substrate and constituting a GND plane of the antenna, and provided between the radiating element and the GND. A high-frequency module with an antenna having a space defined.
[0010]
Embodiments and Examples of the Invention
FIG. 1 is a longitudinal sectional view showing a high-frequency module with antenna AM1 according to an embodiment of the present invention.
[0011]
FIG. 2 is a perspective view showing the high-frequency module with antenna AM1.
[0012]
The high-frequency module with antenna AM1 includes an RF substrate 10, an RF circuit 20, a radiating element 31 of an antenna, a GND 40, a space 50, and a frame 60.
[0013]
The RF substrate 10 constitutes the RF circuit 20 and is made of a resin or a hybrid material obtained by mixing a resin and an inorganic material, and signal lines such as a strip line, a microstrip line, a power supply line, and a connection line are provided. This is a patterned substrate.
[0014]
The RF circuit 20 is a front-end part of the transmission / reception circuit, and is configured on the RF board 10. The RF circuit 20 includes a semiconductor element 21 such as a bare chip, a functional chip component such as a SAW filter 22, a TCXO (temperature-compensated crystal oscillator) 23, a large-capacity capacitor that cannot be built into a substrate, a large-value inductor, and a chip resistor. It has RF components such as passive elements.
[0015]
On the RF substrate 10, a passive element such as an inductor 11, a capacitor 12, a resistor 13, and a strip line 14, a VCO 15, a coupler 16, a balun 17, and an antenna switch module 18 are provided. Note that a passive element portion is included inside the RF substrate 10, and semiconductor elements such as a transistor and a diode switch are mounted on the RF substrate 10.
[0016]
The antenna switch module 18 is a module that includes at least one antenna switch, such as a combination of a diplexer (diplexer) and an antenna switch, and may be provided on the RF board 10.
[0017]
The VCO 15 and the antenna switch module 18 are configured by functional components such as the inductor 11, the capacitor 12, the resistor 13, the strip line 14, and the semiconductor element 21 mounted on the surface of the RF board 10.
[0018]
The antenna 30 forms a planar inverted-F antenna by the radiating element 31, the GND 40, and the space 50. When an inverted F antenna is used as the antenna 30, as shown in FIG. 2, a GND short-circuit line 72 is required in addition to the feed line 71. The GND short-circuit line 72 connects the radiating element 31 and the GND 40 in a DC manner. Is what you do. The impedance of the antenna 30 can be adjusted by the two lines 71 and 72.
[0019]
The radiating element 31 is a radiating element that is provided on the side opposite to the side on which the RF component is mounted when viewed from the RF board 10 and faces the RF board 10. The radiating element 31 is configured by performing a process such as punching on a metal such as copper or aluminum.
[0020]
The GND 40 is one surface of the RF substrate 10 and is provided on the radiating element 31 side, and forms a GND surface of the antenna 30.
[0021]
The space 50 is provided between the radiating element 31 and the GND 40, and air exists in the space 50.
[0022]
The frame 60 maintains the space between the radiating element 31 and the GND 40 at a predetermined distance, secures the space 50, and includes the protrusion 61.
[0023]
The protruding portion 61 is a part of the frame body 60, and as viewed from the RF substrate 10, each of the RF components (functional chip components such as the semiconductor element 21, the SAW filter 22, the TCXO 23, etc.) This is a part protruding from a large-capacity capacitor that cannot be built into the substrate, a large-value inductor, a passive element such as a chip resistor, or the like.
[0024]
The power supply line 71 is a line that electrically connects the RF substrate 10 and the radiation element 31.
[0025]
FIG. 3 is a perspective view showing a state where the high-frequency module with antenna AM1 is mounted on the communication device C1.
[0026]
The communication device C1 is a mobile communication device such as a mobile phone, and includes a high-frequency module with antenna AM1, a housing 91, a display 92, a printed circuit board 93, a shield case 94, and a battery 95.
[0027]
The high-frequency module with antenna AM1 is mounted inside the communication device C1, the antenna 30 is mounted on the edge of a printed circuit board 93, and a display 92, a shield case 94, a battery 95 and the like are mounted near the antenna 30. If the antenna 30 is an inverted-F antenna or a patch antenna, it is relatively hard to be affected by the surroundings, so that other components (such as the battery 95) can be arranged very close to the antenna 30.
[0028]
FIG. 4 is a cross-sectional view of the communication device C1 on which the high-frequency module with antenna AM1 is mounted.
[0029]
As shown in FIG. 4, the high-frequency module with antenna AM1 is directly mounted on the printed circuit board 93. The radiating element 31 of the antenna 30 is mounted so as to be arranged on the surface opposite to the display 92.
[0030]
In addition, the high-frequency module with antenna AM1 is fixed to the printed circuit board 93 by screws 96 and the like. In this case, the high-frequency module with antenna AM1 and the printed circuit board 93 are connected by contact rubber 97 (anisotropic conductive rubber) or the like. .
[0031]
FIG. 5 is a block diagram showing a circuit configuration of the communication device C1, and is a circuit diagram for a dual type mobile phone of GSM and DCS.
[0032]
The circuit function of the RF circuit 10 may be divided into blocks of an arbitrary scale, and may be divided into, for example, a midscale 100, a large scale 200, and the like. Here, the mid-scale 100 includes a DIP (Duplexer), a SW (Antenna Switch), an LPF (Low Pass Filter), a Band Pass Filter (SAW Filter) 22, a Coupler (Coupler), and a PA (Power Amplifier). , APC (auto power controller). In this case, other circuits are configured on the printed circuit board 93. The SAW filter is a filter using a surface acoustic wave, and falls in the category of a bandpass filter in a circuit configuration.
[0033]
The large scale 200 is a circuit that includes, in addition to the contents of the midscale 100, a Balun, an RF-IC, a VCO (voltage controlled oscillator), a TCXO (temperature compensated crystal oscillator), and a loop filter.
[0034]
The high-frequency module with an antenna is configured for each block of this arbitrary scale.
[0035]
The configuration of the communication device C1 is not limited to the above two types, but at least the antenna 30 and the circuit directly connected from the antenna 30 need to be configured as described above.
[0036]
FIG. 6 is an exploded perspective view of the high-frequency module AM1 with an antenna, and is an exploded perspective view showing a configuration of the frame 60 and a method of connecting the RF substrate 10 and the radiating element 31 of the antenna 30 to the frame 60. .
[0037]
As shown in FIG. 6, the radiating element 31 of the antenna 30 is provided with a feeder line 71 and a GND pin 73, and constitutes a radiating element of an inverted F antenna. The frame body 60 is provided with a step and a groove for fixing the radiating element 31, the feed line 71, and the GND pin 73. Although not shown in FIG. 6, a step for fixing the RF substrate 10 is provided on the RF substrate 10 side of the frame body 60 in the same manner as the step.
[0038]
Further, a screw hole 96h for fixing the frame body 60 to the main board of the communication device C1 is provided.
[0039]
The power supply terminal pad 98 and the GND 40 are provided on the radiating element 31 side (the side opposite to the component mounting surface) of the RF board 10, and the power supply line 71 and the GND pin 73 are pressed against the power supply terminal pad 98 and the GND 40. Thus, the power supply line 71 and the GND pin 73 are electrically connected.
[0040]
The connection between the power supply line 71 and the power supply terminal pad 98 and the connection between the GND pin 73 and the GND 40 are performed by an adhesive or a clip provided on the frame 60.
[0041]
Next, the materials used in the above embodiments will be described.
[0042]
As the resin material of the RF substrate 10, a thermosetting resin or a thermoplastic resin can be used.
[0043]
As thermosetting resin, epoxy resin, phenol resin, unsaturated polyester resin, vinyl ester resin, polyimide resin, polyphenylene ether (oxide) resin, bismaleimide triazine (cyanate ester) resin, fumarate resin, polybutadiene resin, polyvinyl benzyl ether compound Resin or the like is assumed.
[0044]
As the thermoplastic resin, an aromatic polyester resin, a polyphenylene sulfide resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polyethylene sulfide resin, a polyetheretherketone resin, a polytetrafluoroethylene resin, a graft resin, and the like are assumed.
[0045]
Among them, phenol resin, epoxy resin, low dielectric constant epoxy resin, polybutadiene resin, BT resin, vinylbenzyl resin and the like are particularly preferable as the base resin. These resins may be used alone or as a mixture of two or more. When two or more types are used in combination, the mixing ratio is arbitrary. Alternatively, examples of the inorganic material for forming the hybrid material include the following. In order to obtain a relatively high dielectric constant, it is particularly preferable to use the following materials.
[0046]
Titanium-barium-neodymium ceramics, titanium-barium-tin ceramics, lead-calcium ceramics, titanium dioxide ceramics, barium titanate ceramics, lead titanate ceramics, strontium titanate ceramics, calcium titanate ceramics Ceramics, bismuth titanate ceramics, magnesium titanate ceramics, CaWO ₄ ceramics, Ba (Mg, Nb) O ₃ ceramics, Ba (Mg, Ta) O ₃ ceramics, Ba (Co, Mg, Nb) O ₃ type ceramics, Ba (Co, Mg, Ta) O ₃ type ceramics.
[0047]
It should be noted that the titanium dioxide-based ceramics include those containing only a small amount of additives in addition to those containing only titanium dioxide, and which retain the crystal structure of titanium dioxide. The same applies to other ceramics. In particular, the titanium dioxide ceramic preferably has a rutile structure.
[0048]
In order to obtain a high Q without increasing the dielectric constant too much, it is preferable to use the following materials.
[0049]
Silica, alumina, zirconia, potassium titanate whiskers, calcium titanate whiskers, barium titanate whiskers, zinc oxide whiskers, glass chops, glass beads, carbon fibers, magnesium oxide (talc).
[0050]
These may be used alone or in combination of two or more. When two or more types are used in combination, the mixing ratio is arbitrary.
[0051]
When a magnetic material is used as the inorganic material, the ferrite is a Mn-Mg-Zn-based, Ni-Zn-based, Mn-Zn-based, or the like, and preferably a Mn-Mg-Zn-based or Ni-Zn-based. As ferromagnetic metals, carbonyl iron, iron-silicon alloy, iron-aluminum-silicon alloy (trade name: Sendust), iron-nickel alloy (trade name: Permalloy), amorphous type (iron type, cobalt type), etc. Is preferred.
[0052]
Further, as the metal pattern to be used, a suitable pattern may be used from metals having good conductivity such as gold, silver, copper, and aluminum. Of these, copper is particularly preferred.
[0053]
As the RF circuit (front end circuit) 20, at least one of a duplexer, an antenna switch, a low-pass filter, a band-pass filter, a power amplifier, a coupler, a balun, an RFIC, a VCO, and a TCXO is provided.
[0054]
When connecting the RF circuit 20 and the printed circuit board 93 including the baseband circuit, an anisotropic conductive sheet is used.
[0055]
In the above embodiment, a patch antenna may be used as the antenna 30 instead of the inverted F antenna.
[0056]
In the above embodiment, the RF circuit 20 may be provided on the side surface of the frame body 60.
[0057]
Further, in the above-described embodiment, a columnar body or a plate-like body may be used instead of the frame-like body 60, and a member obtained by a foam forming method in a region where the space 50 exists, For example, countless spaces or honeycomb-shaped cavities made of Styrofoam may be provided, and the space between the antenna 30 and the GND 40 may be maintained at a predetermined distance by the countless spaces or honeycomb-shaped cavities made of Styrofoam.
[0058]
In the above embodiment, at least one of a duplexer, an antenna switch, a low-pass filter, a band-pass filter, a power amplifier, a coupler, a balun, an RFIC, a VCO, and a TCXO may be provided as the RF circuit 20. .
[0059]
Although the area occupied by the built-in antenna in the portable device is very large, in the above embodiment, since the RF circuit 20 is configured in the space, a great space advantage can be obtained.
[0060]
Further, according to the above embodiment, since the built-in antenna 30 is an inverted-F antenna or a patch antenna, it is possible to mount circuit components on the surface of the GND 40 (the surface of the GND 40 opposite to the radiating element 31). Since the restriction on the mounting position is reduced and a general printed circuit board laminating method can be used for the RF substrate 10, it is not necessary to adopt a cavity configuration or an embedded configuration, and therefore, the configuration is easy. Yes, the cost can be reduced.
[0061]
Further, according to the above embodiment, the set side can significantly reduce the management cost and the mounting cost by greatly reducing the number of components.
[0062]
According to the above-described embodiment, since the antenna 30 and the RF circuit 20 are integrated, it is possible to eliminate troublesome operations such as matching adjustment between the antenna 30 and the RF circuit 20 on the set side.
[0063]
Further, according to the above embodiment, since it is not necessary to make the impedance between the antenna 30 and the RF circuit 20 a 50Ω system, matching loss is reduced and the number of components is reduced.
[0064]
Accordingly, in the above embodiment, a compact, low-cost, high-performance mobile communication device with a built-in antenna can be realized.
[0065]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the whole area of a high frequency antenna module does not become large, a circuit component can be mounted on a GND surface, and the manufacturing process of a high frequency antenna module is simple.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a high-frequency module with antenna AM1 according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a high-frequency module with antenna AM1.
FIG. 3 is a perspective view showing a state where the high-frequency module with antenna AM1 is mounted on a communication device C1.
FIG. 4 is a cross-sectional view of the communication device C1 on which the high-frequency module with antenna AM1 is mounted.
FIG. 5 is a block diagram showing a circuit configuration of the communication device C1, which is a circuit diagram for a dual type mobile phone of GSM and DCS.
FIG. 6 is an exploded perspective view of the high-frequency module with antenna AM1, which is an exploded perspective view showing a configuration of the frame body 60 and a method of connecting the RF substrate 10 and the radiating element 31 of the antenna 30 to the frame body 60. .
[Explanation of symbols]
AM1… High-frequency module with antenna,
10 RF board,
20 RF circuit,
30 ... antenna,
31 ... radiating element,
40 ... GND,
50… space,
60 ... frame-like body,
71 ... feed line,
72 ... GND,
91 ... housing,
92 ... display,
93 ... Printed circuit board,
94 ... Shield case,
95 ... battery.

Claims (7)

An RF board on which RF components constituting an RF circuit are mounted;
A radiating element for an antenna, which is provided on the side opposite to the side on which the RF component is mounted as viewed from the RF substrate and faces the RF substrate;
One surface of the RF substrate, which is provided on the radiation element side and constitutes a GND surface of the antenna;
A space provided between the radiating element and the GND;
A high-frequency module with an antenna, comprising: In claim 1,
It has a frame, a column, or a plate for maintaining the distance between the radiating element and the GND at a predetermined distance, and the space is secured by the frame, the column, or the plate. A high-frequency module with an antenna, characterized in that: In claim 1,
An interval between the radiating element and the GND is maintained at a predetermined distance by providing innumerable spaces or honeycomb-shaped cavities formed of constituent members obtained by the foam forming method between the radiating element and the GND. A high-frequency module with an antenna, wherein the space is secured by an infinite number of spaces formed of the constituent members obtained by the foaming method or the honeycomb-shaped cavity. In claim 2 or claim 3,
The RF component is mounted on at least one side of the frame-shaped body, the columnar body, the plate-shaped body, the countless spaces formed by the components obtained by the foam forming method, and the honeycomb-shaped cavity. A high-frequency module with an antenna, comprising: In claim 1,
The high-frequency module with an antenna, wherein the RF circuit is at least one of a duplexer, an antenna switch, a low-pass filter, a band-pass filter, a power amplifier, a coupler, a balun, an RFIC, a VCO, and a TCXO. In claim 1,
A high-frequency module with an antenna, wherein an anisotropic conductive sheet is used for connection between the RF circuit and a printed circuit board including a baseband circuit. In claim 1,
The high-frequency module with an antenna, wherein the antenna is an inverted-F antenna or a patch antenna.

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