An on-board FM antenna and radio

Abstract

The utility model discloses a kind of on-board FM antennas and radio, on-board FM antenna includes impedance matching circuit, antenna body;Antenna body is electrically connected with impedance matching circuit;Antenna body is planar helix structure, for signal transceiving.By the antenna body is planar helix structure, multiple first strip traces of planar helix structure are mutually parallel, made on circuit board, form first capacitor, multiple second strip traces of planar helix structure are mutually parallel, made in the interlayer of circuit board, form second capacitor, multiple first strip traces are sequentially spaced apart from the multiple second strip traces respectively connected, form planar helix structure, form first inductance, not only expand antenna length, also save space, solve the problem that the effective length of antenna is shortened, and then influence antenna transceiving effect caused by the unreasonable design of existing built-in antenna structure.

Description

Technical Field

[0001] This utility model relates to the field of FM onboard antenna technology, and in particular to an onboard FM antenna and radio. Background Technology

[0002] FM antennas are mainly divided into two categories: internal and external. Both operate on the principle of electromagnetic induction—generating an induced current by cutting electromagnetic waves through a conductor, which is then amplified and demodulated to reconstruct the audio signal. The design differences between different types of antennas are primarily to adapt to the reception requirements of different scenarios (such as sensitivity, directivity, and ease of installation).

[0003] When electromagnetic waves (FM signals) reach the antenna, the free electrons in the conductor vibrate under the influence of the electric field, generating an alternating current. The current is transmitted to the receiver via the feeder, where the target frequency is selected through the tuning circuit (LC resonance), and then amplified and demodulated to obtain the audio signal.

[0004] Antenna length has a significant impact on reception performance. The higher the matching degree with the FM wavelength (approximately 3.4 meters), the stronger the induced current (e.g., 1 / 4 wavelength is approximately 85 cm, 1 / 2 wavelength is approximately 1.7 meters).

[0005] The built-in antenna is integrated inside the device, making it suitable for portable devices. Copper foil is etched on the PCB board as a conductor, and the space on the circuit board is used to form an inductor and capacitor structure to receive signals through electromagnetic coupling.

[0006] However, the existing built-in antenna structure design is unreasonable, which leads to a shortened effective length of the antenna, thus affecting the antenna's transmission and reception performance. Utility Model Content

[0007] The existing built-in antenna structure is poorly designed, resulting in a shortened effective length of the antenna, which in turn affects the antenna's transmission and reception performance.

[0008] To address the aforementioned issues, an onboard FM antenna and radio is proposed. The antenna body is a planar spiral structure. Multiple first-line traces of the planar spiral structure are fabricated parallel to each other on a circuit board to form a first capacitor. Multiple second-line traces of the planar spiral structure are fabricated parallel to each other in the interlayer of the circuit board to form a second capacitor. The multiple first-line traces are sequentially and alternately connected to the multiple second-line traces to form a planar spiral structure, thus forming a first inductor. This not only extends the antenna length but also saves space, solving the problem that the existing built-in antenna structure design is unreasonable, leading to a shortened effective antenna length and thus affecting the antenna's transmission and reception performance.

[0009] Firstly, an onboard FM antenna includes: Impedance matching circuit; Antenna body; The antenna body is electrically connected to the impedance matching circuit. The antenna body has a planar spiral structure and is used for signal transmission and reception.

[0010] In a first possible embodiment of the onboard FM antenna described in this utility model, the antenna body includes: Multiple first-line traces; Multiple second-line traces; The plurality of first strip-shaped traces are parallel to each other and fabricated on the circuit board to form a first capacitor; The plurality of second strip-shaped traces are parallel to each other and are fabricated in the middle of the interlayer of the circuit board to form a second capacitor; The plurality of first strip-shaped traces are sequentially and alternately connected to the plurality of second strip-shaped traces to form the planar spiral structure, thereby forming the first inductor.

[0011] In conjunction with the first possible embodiment of this utility model, in the second possible embodiment, the antenna body further includes: Multiple vias; The plurality of first strip-shaped traces are sequentially and spaced apart from the plurality of second strip-shaped traces through the plurality of vias.

[0012] In conjunction with the second possible implementation of this utility model, in the third possible implementation, both ends of each second strip-shaped trace are respectively connected to the end of the previous first strip-shaped trace and the beginning of the next first strip-shaped trace through vias.

[0013] In conjunction with the third possible implementation of this utility model, in the fourth possible implementation, the plurality of first strip-shaped traces are made of copper foil and are formed on the circuit board by etching.

[0014] In conjunction with the fourth possible embodiment of this utility model, and in the fifth possible embodiment, the impedance matching circuit includes: Third capacitor, second inductor, first diode, second diode; The first terminal of the third capacitor, the first terminal of the second inductor, the cathode of the first diode, and the anode of the second diode are electrically connected to the antenna body through an antenna socket. The second terminal of the third capacitor, the second terminal of the second inductor, the anode of the first diode, and the cathode of the second diode are all connected together and then grounded.

[0015] In a sixth possible embodiment of the onboard FM antenna described in this utility model, the onboard FM antenna receives FM band frequencies ranging from 87 to 108 MHz.

[0016] In a second aspect, a radio receiver includes the onboard FM antenna described in the first aspect, comprising: Control circuit; Frequency modulation circuit; The frequency modulation circuit is electrically connected to the onboard FM antenna. The frequency modulation circuit is electrically connected to the control circuit and is used to process the signal received by the onboard FM antenna according to the control command, and output the processed audio signal through the left and right channels.

[0017] In conjunction with the radio described in the second aspect, in a first possible implementation, the radio further includes an output circuit; The output circuit is electrically connected to the frequency modulation circuit and is used to output audio signals.

[0018] In conjunction with the first possible implementation of the second aspect, in the second possible implementation, the radio further includes a linear voltage circuit; The linear voltage circuit is electrically connected to the frequency modulation circuit and is used to output a linear voltage to the frequency modulation circuit.

[0019] The onboard FM antenna and radio described in this utility model are constructed by making the antenna body a planar spiral structure, fabricating multiple first-line traces of the planar spiral structure parallel to each other on a circuit board to form a first capacitor, and fabricating multiple second-line traces of the planar spiral structure parallel to each other in the middle of the circuit board to form a second capacitor. The multiple first-line traces are sequentially and space-divided with the multiple second-line traces to form a planar spiral structure to form a first inductor. This not only extends the antenna length but also saves space, solving the problem that the existing built-in antenna structure design is unreasonable, resulting in a shortened effective antenna length and thus affecting the antenna's transmission and reception performance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an overall structural diagram of the onboard FM antenna in this utility model; Figure 2 This is a circuit diagram of the impedance matching circuit and frequency modulation circuit of the radio in this utility model. Figure 3 This is a schematic diagram of the output circuit of the radio in this utility model; Figure 4This is a schematic diagram of the linear voltage circuit of the radio in this utility model; Components and their serial numbers: 100 – Onboard FM antenna, 110 – First strip trace, 120 – Second strip structure, 130 – Via. Detailed Implementation

[0022] The technical solutions of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of this utility model.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0025] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] The existing built-in antenna structure is poorly designed, resulting in a shortened effective length of the antenna, which in turn affects the antenna's transmission and reception performance.

[0028] To address the above issues, an onboard FM antenna 100 and a radio are proposed.

[0029] Firstly, such as Figure 1 , Figure 1 This is an overall structural diagram of the onboard FM antenna 100 of this utility model; an onboard FM antenna 100 includes an impedance matching circuit and an antenna body; the antenna body is electrically connected to the impedance matching circuit; the antenna body has a planar spiral structure and is used for signal transmission and reception.

[0030] In this embodiment, the antenna body is a planar spiral structure and is fabricated on a circuit board, which can save space and extend the antenna length, thereby improving the signal reception effect.

[0031] In one possible implementation, the antenna body includes a plurality of first strip-shaped traces 110 and a plurality of second strip-shaped traces 120; the plurality of first strip-shaped traces 110 are parallel to each other and fabricated on a circuit board to form a first capacitor; the plurality of second strip-shaped traces 120 are parallel to each other and fabricated in the middle of the circuit board to form a second capacitor; the plurality of first strip-shaped traces 110 and the plurality of second strip-shaped traces 120 are sequentially and spaced apart to form a planar spiral structure to form a first inductor.

[0032] In one possible implementation, the antenna body further includes a plurality of vias 130; a plurality of first strip-shaped traces 110 are sequentially and spaced apart from a plurality of second strip-shaped traces 120 through the plurality of vias 130.

[0033] In one possible implementation, the two ends of each second strip 120 are connected to the end of the previous first strip 110 and the beginning of the next first strip 110 respectively through vias 130.

[0034] In one possible implementation, a plurality of first strip-shaped traces 110 are made of copper foil and are formed on the circuit board by etching.

[0035] In this embodiment, the FM antenna 100 is effectively integrated onto the PCB board, improving upon the previously long FM length and solving the problems of poor soldering and inconvenient assembly. This also significantly reduces costs while achieving good reception. It can be widely used in speaker systems, home theaters, outdoor mobile devices, etc.

[0036] In one possible implementation, such as Figure 2 , Figure 2 The circuit diagrams for the impedance matching circuit and frequency modulation circuit of the radio in this utility model are shown below; the circuit structure diagram of the impedance matching circuit is shown below. Figure 2It includes a third capacitor C67, a second inductor L3, a first diode D5, and a second diode D6; the first terminal of the third capacitor C67, the first terminal of the second inductor L3, the cathode of the first diode D5, and the anode of the second diode D6 are electrically connected to the antenna body through an antenna socket; the second terminal of the third capacitor C67, the second terminal of the second inductor L3, the anode of the first diode D5, and the cathode of the second diode D6 are connected together and then grounded.

[0037] In this embodiment, by making the antenna body a planar spiral structure, multiple first strip-shaped traces 110 of the planar spiral structure are fabricated parallel to each other on a circuit board to form a first capacitor, and multiple second strip-shaped traces 120 of the planar spiral structure are fabricated parallel to each other in the middle of the circuit board to form a second capacitor. The multiple first strip-shaped traces 110 and multiple second strip-shaped traces 120 are sequentially and space-divided to form a planar spiral structure to form a first inductor. This not only extends the antenna length but also saves space, solving the problem that the existing built-in antenna structure design is unreasonable, resulting in a shortened effective length of the antenna, which in turn affects the antenna's transmission and reception performance.

[0038] In a second aspect, a radio includes an onboard FM antenna 100 as described in the first aspect, and includes a control circuit and a frequency modulation circuit; the frequency modulation circuit is electrically connected to the onboard FM antenna 100; the frequency modulation circuit is electrically connected to the control circuit and is used to process the signal received by the onboard FM antenna 100 according to control instructions, and output the processed audio signal through the left and right channels.

[0039] like Figure 2 The frequency modulation chip U9 of the frequency modulation circuit is electrically connected to the control circuit through FM_SCL and FM_SDA. The frequency modulation chip U9 is electrically connected to the output circuit through FML_OUT and FMR_OUT, and electrically connected to the linear voltage circuit through FM_3V1.

[0040] The U9 frequency modulation chip integrates an RF amplifier, frequency converter, bandpass filter, demodulator, and audio amplifier to demodulate the received audio signal.

[0041] In one possible implementation, such as Figure 3 , Figure 3 This is a schematic diagram of the output circuit of the radio in this utility model; the radio also includes an output circuit; the output circuit is electrically connected to the frequency modulation circuit and is used to output audio signals.

[0042] In one possible implementation, such as Figure 4 , Figure 4 This is a schematic diagram of the linear voltage circuit of the radio in this utility model; the radio also includes a linear voltage circuit; the linear voltage circuit is electrically connected to the frequency modulation circuit and is used to output a linear voltage to the frequency modulation circuit.

[0043] The principle of the onboard FM antenna 100 of the radio in this embodiment is as follows: At the ANT antenna receiving end, the FM radio's antenna receives the radio waves emitted by the transmitting end. The received signal (87-108MHz) first passes through the RF amplifier of the FM circuit to amplify the signal. Then, the signal enters the frequency converter of the FM circuit, converting the signal into an intermediate frequency (IF) signal. Demodulation process: The IF signal passes through the bandpass filter of the FM circuit to remove unwanted frequency components. Then, the signal enters a demodulator to restore the frequency-modulated signal to the original audio signal. Amplification and output: Finally, the demodulated audio signal passes through the audio amplifier of the FM circuit to amplify the signal. The signal is then converted into audible sound through a speaker, achieving complete FM reception.

[0044] The onboard FM antenna 100 and radio implementing this utility model, by making the antenna body a planar spiral structure, fabricating multiple first strip-shaped traces 110 of the planar spiral structure parallel to each other on a circuit board to form a first capacitor, fabricating multiple second strip-shaped traces 120 of the planar spiral structure parallel to each other in the middle of the circuit board to form a second capacitor, and connecting the multiple first strip-shaped traces 110 and the multiple second strip-shaped traces 120 sequentially and alternately to form a planar spiral structure to form a first inductor, not only extends the antenna length but also saves space, solving the problem that the existing built-in antenna structure design is unreasonable, resulting in a shortened effective antenna length, which in turn affects the antenna's transmission and reception performance.

[0045] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An onboard FM antenna, characterized in that, include: Impedance matching circuit; Antenna body; The antenna body is electrically connected to the impedance matching circuit. The antenna body has a planar spiral structure and is used for signal transmission and reception. The antenna body includes: Multiple first-line traces; Multiple second-line traces; The plurality of first strip-shaped traces are parallel to each other and fabricated on the circuit board to form a first capacitor; The plurality of second strip-shaped traces are parallel to each other and are fabricated in the middle of the interlayer of the circuit board to form a second capacitor; The plurality of first strip-shaped traces are sequentially and alternately connected to the plurality of second strip-shaped traces to form the planar spiral structure, thereby forming the first inductor.

2. The onboard FM antenna according to claim 1, characterized in that, The antenna body also includes: Multiple vias; The plurality of first strip-shaped traces are sequentially and spaced apart from the plurality of second strip-shaped traces through the plurality of vias.

3. The onboard FM antenna according to claim 2, characterized in that, Both ends of each second strip are connected to the end of the previous first strip and the beginning of the next first strip through vias, respectively.

4. The onboard FM antenna according to claim 3, characterized in that, The plurality of first strip-shaped traces are made of copper foil and are formed on the circuit board by etching.

5. The onboard FM antenna according to claim 4, characterized in that, The impedance matching circuit includes: Third capacitor, second inductor, first diode, second diode; The first terminal of the third capacitor, the first terminal of the second inductor, the cathode of the first diode, and the anode of the second diode are electrically connected to the antenna body through an antenna socket. The second terminal of the third capacitor, the second terminal of the second inductor, the anode of the first diode, and the cathode of the second diode are all connected together and then grounded.

6. The onboard FM antenna according to any one of claims 1-5, characterized in that, The onboard FM antenna receives FM band frequencies ranging from 87 to 108 MHz.

7. A radio, comprising the onboard FM antenna of claim 6, characterized in that, include: Control circuit; Frequency modulation circuit; The frequency modulation circuit is electrically connected to the onboard FM antenna. The frequency modulation circuit is electrically connected to the control circuit and is used to process the signal received by the onboard FM antenna according to the control command, and output the processed audio signal through the left and right channels.

8. The radio according to claim 7, characterized in that, The radio also includes an output circuit; The output circuit is electrically connected to the frequency modulation circuit and is used to output audio signals.

9. The radio according to claim 8, characterized in that, The radio also includes a linear voltage circuit; The linear voltage circuit is electrically connected to the frequency modulation circuit and is used to output a linear voltage to the frequency modulation circuit.

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