Patent Publication Number: US-2021184341-A1

Title: Antenna apparatus for vehicles, and method of receiving broadcasting by using the antenna apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0168657, filed on Dec. 17, 2019, and Patent Application No. 10-2020-0010076, filed on Jan. 28, 2020, in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     The disclosure relates to antennas. More particularly, the disclosure relates to an antenna apparatus mounted on a vehicle to receive broadcasting, and a method of receiving broadcasting by using the antenna apparatus. 
     2. Description of the Related Art 
     With developments in communication technology, listening or watching broadcasted media such as radio broadcasting or television broadcasting in vehicles has become common. An antenna should be installed on a vehicle to receive broadcasting, and the installation location of the antenna directly affects performance of the antenna, stability of the vehicle, and the aesthetics of the vehicle. Currently, most antennas are installed within a shark fin module located on a glass or roof of vehicles. 
     When an antenna is installed on the glass of a vehicle, damage to the glass due to external impacts may bring damage to the antenna, and a long cable is needed to connect the antenna to a printed circuit board (PCB) module. When two or more antennas are installed on the glass to support diversity, an isolation issue between the antennas may occur. 
     Because shark fin modules are shaped to be exposed to the outside of antennas, there is a high risk of damage due to external impacts. Moreover, smaller shark fin modules require smaller-sized antennas. Smaller antennas are subject to, deterioration in radiation capability (or broadcasting reception capability). When several antennas are installed to receive various broadcasting signals, the number and/or size of shark fin modules are increased. 
     SUMMARY 
     According to certain embodiments, an antenna apparatus comprises: an antenna configured to be located below a metal panel of a vehicle; a printed circuit board (PCB) module electrically connected to the antenna; and at least one ground extender configured to electrically connect a ground of the PCB module to the metal panel, receive current from the PCB module, and provide the current from the PCB module to the metal panel. 
     According to certain embodiments, the antenna is configured to have a resonance frequency determined according to a location on a ground region of the PCB module where the at least one ground extender is arranged. 
     According to certain embodiments, the at least one ground extender comprises a plurality of ground extenders arranged at different locations within a ground region of the PCB module, and the PCB module comprises a control unit configured to receive a request to change a frequency to a target frequency from a broadcasting receiver, and to control a switch so that a current flows to a particular one of the plurality of ground extenders corresponding to the target frequency. 
     According to certain embodiments, the antenna apparatus further comprises a lifting module configured to receive a request to change a frequency to a target frequency from a broadcasting receiver and adjust a gap between the metal panel and the antenna according to the target frequency. 
     According to certain embodiments, the PCB module comprises: a variable impedance device located on a current path; and a control unit configured to receive a request to change a frequency to a target frequency from a broadcasting receiver and change a value of the variable impedance device according to the target frequency. 
     According to certain embodiments, the antenna is configured to be located between the metal panel and a dielectric panel. 
     According to certain embodiments, the metal panel comprises at least one of a hood panel, a trunk panel, a door panel, a fender panel, a bumper panel, a pillar panel, or a roof panel. 
     According to certain embodiments, a method of receiving broadcasting by using an antenna apparatus comprises: converting a broadcasting signal into a current by an antenna located below a metal panel of a vehicle; and amplifying the current and transmitting an amplified current to a broadcasting receiver by a printed circuit board (PCB) module, and providing a current flowing in a ground of the PCB module to the metal panel through at least one ground extender arranged on the ground of the PCB module. 
     According to certain embodiments, the at least one ground extender comprises a plurality of ground extenders arranged at different locations within a ground region of the PCB module, and wherein the method further comprises receiving, by the PCB module, a request to change a frequency from the broadcasting receiver to a target frequency and controlling a switch so that a current flows to a particular one of the at least one ground extender corresponding to the target frequency. 
     According to certain embodiments, the method further comprises receiving, by a lifting module, a request to change a frequency from the broadcasting receiver to a target frequency and adjusting a gap between the metal panel and the antenna according to the target frequency to which the frequency is changed. 
     According to certain embodiments, the method further comprises receiving, by the PCB module, a request to change a frequency from the broadcasting receiver to a target frequency, and changing a value of a variable impedance device located on a current path according to the target frequency to which the frequency is changed. 
     According to certain embodiments, a vehicle comprises a frame comprising at least one metal panel forming an exterior surface of the vehicle; an antenna disposed below the at least one metal panel in an interior of the vehicle; a printed circuit board (PCB) module electrically connected to the antenna; and at least one ground extender electrically connecting a ground of the PCB module to the metal panel, wherein the ground extender is configured to receive current from the PCB module, and provide the current from the PCB module to the metal panel. 
     According to certain embodiments, the antenna is configured to have a resonance frequency determined according to a location on a ground region of the PCB module where the at least one ground extender is arranged. 
     According to certain embodiments, the vehicle comprises a broadcasting receive configured to receive a signal from the PCB module, and wherein the at least one ground extender comprises a plurality of ground extenders arranged at different locations within a ground region of the PCB module, and wherein the PCB module comprises a control unit configured to receive a request to change a frequency from the broadcasting receiver to a target frequency, and to control a switch so that a current flows to a particular one of the plurality of ground extenders corresponding to the target frequency. 
     According to certain embodiments, the vehicle further comprises a broadcast receive configured to receive a signal from the PCB and a lifting module configured to receive a request to change a frequency from the broadcasting receiver to a target frequency and adjust a gap between the at least one metal panel and the antenna according to the target frequency to which the frequency is changed. 
     According to certain embodiments, the vehicle further comprises a broadcasting receiver configured to receive and output a signal from the PCB, and wherein the PCB module comprises: a variable impedance device located on a current path; and a control unit configured to receive a request to change a frequency from the broadcasting receiver to a target frequency and change a value of the variable impedance device according to the request to change the frequency. 
     According to certain embodiments, the vehicle further comprises a dielectric panel, wherein the antenna is disposed between the at least one metal panel and the dielectric panel. 
     According to certain embodiments, the at least one metal panel comprises at least one of a hood panel, a trunk panel, a door panel, a fender panel, a bumper panel, a pillar panel, or a roof panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
       A brief description of each drawing is provided to better understand the drawings cited herein. 
         FIG. 1  is a schematic view of an antenna apparatus installed in a vehicle, according to an embodiment of the disclosure; 
         FIG. 2  is diagram of a vehicle comprising one or more metal panels where an antenna apparatus can be installed; 
         FIG. 3  is a schematic view of an antenna apparatus according to an embodiment of the disclosure; 
         FIG. 4  illustrates a printed circuit board (PCB) module according to an embodiment of the disclosure; 
         FIG. 5  is graphs comparing radiation characteristics according to presence or absence of a ground extender within an antenna apparatus; 
         FIG. 6  is graphs comparing characteristics of a current flowing in a metal panel of a vehicle according to presence or absence of a ground extender within an antenna apparatus; 
         FIG. 7  is graphs comparing radiation characteristics according to arrangement locations of a ground extender within an antenna apparatus; 
         FIG. 8  illustrates a PCB module according to another embodiment of the disclosure; 
         FIG. 9  illustrates a PCB module according to another embodiment of the disclosure; 
         FIG. 10  is a graph showing radiation characteristics according to the value of a variable impedance device within a PCB module; 
         FIG. 11  is a schematic view of an antenna apparatus according to another embodiment of the disclosure; 
         FIG. 12  is a graph showing radiation characteristics of an antenna apparatus according to a gap between an antenna and a metal panel; 
         FIG. 13  is a schematic view of an antenna apparatus according to another embodiment of the disclosure; and 
         FIG. 14  is a flowchart of a method of receiving broadcasting by an antenna apparatus, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     As the disclosure allows for various changes and numerous examples, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the disclosure to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the spirit and technical scope of the disclosure are encompassed in the disclosure. 
     In the description of embodiments, certain detailed explanations of related art are omitted when it is deemed that they may unnecessarily obscure the essence of the disclosure. Also, numbers (for example, a first, a second, and the like) used in the description of embodiments are merely identifier codes for distinguishing one element from another. 
     Also, in the present specification, it will be understood that when elements are “connected” or “coupled” to each other, the elements may be directly connected or coupled to each other, but may alternatively be connected or coupled to each other with an intervening element therebetween, unless specified otherwise. 
     In the present specification, regarding an element represented as a “unit” or a “module”, two or more elements may be combined into one element or one element may be divided into two or more elements according to subdivided functions. In addition, each element described hereinafter may additionally perform some or all of functions performed by another element, in addition to main functions of itself, and some of the main functions of each element may be performed entirely by another component. 
     Throughout the disclosure, the expression “at least one of a, b or c” indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. 
     Embodiments of the disclosure will now be sequentially described more fully with reference to the accompanying drawings. 
     Provided are an antenna apparatus for vehicles receives broadcast radio without exposure to the outside of vehicles, a vehicle include an antenna apparatus, and a method of receiving broadcasting by using an antenna apparatus. 
     Provided are an antenna apparatus for vehicles that has an improved radiation capability due to extension of the ground of a printed circuit board (PCB) module connected to an antenna, a vehicle including an antenna apparatus that has an improved radiation capability due to extension of the ground of a PCB, and a method of receiving broadcasting by using the antenna apparatus. 
     Provided are an antenna apparatus for vehicles that is able to receive broadcasting signals of various frequencies, a vehicle including an antenna apparatus that is able to receive broadcasting signals of various frequencies, and a method of receiving broadcasting by using the antenna apparatus. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure. 
       FIG. 1  is a schematic view of an antenna apparatus  100  installed in a vehicle  10 , according to an embodiment of the disclosure. 
     The antenna apparatus  100  is installed below a metal panel  20  (such as a roof panel) forming an exterior surface of the vehicle  10 . Accordingly, the antenna apparatus  100  is not exposed to the outside of the vehicle  10 . 
     Referring to  FIG. 1 , the antenna apparatus  100  may be installed in a space between the metal panel  20  of the vehicle  10  and the dielectric panel  30  located below the metal panel  20 . A space where passengers  1  are boarded is located below the dielectric panel  30 . 
     Because the antenna apparatus  100  is located in a space below the metal panel  20  of the vehicle  10 , the antenna apparatus  100  does not affect the aesthetics of the vehicle  10  and is not easily destroyed due to external impacts. 
       FIG. 1  illustrates that the antenna apparatus  100  is installed below a roof panel of the vehicle  10 , and this illustration is merely an embodiment. The antenna apparatus  100  can be also installed under a hood panel, trunk panel, inside a door panel, fender panel, bumper panel, pillar panel as will now described with reference to  FIG. 2 . 
       FIG. 2  is a diagram of a vehicle, with a frame with one or more metal panels where the antenna apparatus  100  can be installed. 
     Referring to  FIG. 2 , the antenna apparatus  100  may be installed under or in at least one of a hood panel  11 , a door panel  12 , a fender panel  13 , a pillar panel  14 , a roof panel  15 , a bumper panel  16 , or a truck panel  17  of the vehicle  10 . 
     The door panel  12  may include not only a front door panel of the drivers side shown in  FIG. 2 , front passenger side, and both rear side passenger doors. In the case of a Van or a Sports Utility Vehicle (SUV) with a rear door, the antenna can be included in the rear door, as well. The fender panel  13  can include either the front or rear, on either the driver&#39;s side or passenger&#39;s side. The pillar panel  14  may include not only a front pillar panel on the driver&#39;s seat side shown in  FIG. 2 , but also a rear pillar panel on the driver&#39;s seat side, a front pillar panel on the passengers seat side, and a rear pillar panel on the passenger&#39;s seat side. The bumper panel  16  may include a front bumper panel shown in  FIG. 2  as well as a rear bumper panel. 
     According to an embodiment, the antenna apparatus  100  may be installed according to panels that surround a front windshield, and/or panels that surround a rear windshield. According to an embodiment, when a sunroof is mounted in the vehicle  10 , the antenna apparatus  100  may be installed along panels that surround the sunroof. 
     The locations of  FIG. 2  where the antenna apparatus  100  is installable are examples, and the antenna apparatus  100  may be installed at a number of other points where spaces may be secured, between the metal panel  20  and the dielectric  30  of the vehicle  10 . 
       FIG. 3  is a schematic view of the antenna apparatus  100  according to an embodiment of the disclosure. 
     Referring to  FIG. 3 , the antenna apparatus  100  may include an antenna  110 , a printed circuit board (PCB) module  130 , a feeding line  150 , and at least one ground extender  170 . The antenna  110  is configured to be located below a metal panel of a car, thereby avoiding exposure to the outside of the car and not affecting the aesthetic appearance of the car. The at least one ground extender  170  is configured to connect a ground of the PCB module to the metal panel, thereby improving the radiation capability of the antenna. 
     The antenna  110  receives a broadcasting signal that is broadcast from a radio broadcasting station. The radio broadcasting station transmits a content signal by modulating the content signal to a radio frequency signal, and amplifying the radio signal. The amplified radio signal propagates electromagnetic waves that are mixed with other electromagnetic waves that come from other sources, such as other radio stations, as well as natural sources. The antenna  110  may convert electromagnetic waves into a current. The antenna  110  may include a monopole antenna, a dipole antenna, a loop antenna, or a slot antenna. 
     The PCB module  130  is electrically connected to the antenna  110  through the feeding line  150 , receives the current, filters the current to replicate radio signal from the radio station, amplifies and demodulates the replicated radio signal to replicate the content signal, and transmits the replicated content signal to a broadcasting receiver. The broadcasting receiver may include various apparatuses capable of outputting the replicated content signal, as visual data or audio data. 
     According to an embodiment, the PCB module  130  may include a tuner that matches an impedance of the broadcasting receiver with an impedance of the antenna  110 . 
     The at least one ground extender  170  electrically connects a ground of the PCB module  130  to the metal panel  20  of the vehicle  10 . In detail, the ground extender  170  extends from the PCB module  130  in a vertical direction, and has one end contacting a ground region within the PCB module  130  and the other end contacting the metal panel  20 , so that a current flowing in the ground of the PCB module  130  may flow toward the metal panel  20 . The at least one ground extender  170  may include a conductive material (for example, metal). 
     To improve a capability of receiving a broadcasting signal of a low frequency band, the ground of the PCB module  130  should have a large size equal to or greater than one wavelength (A) of the radio frequency. The ground extender  170  plays a role of increasing the size of the ground of the PCB module  130 . 
     The at least one ground extender  170  increases the size of the ground and enables not only the antenna  110  but also the vehicle  10  to operate as antennas, by electrically connecting the ground of the PCB module  130  to the metal panel  20 . 
     The at least one ground extender  170  may be arranged at various locations within the ground region of the PCB module  130 , and arrangeable locations of the at least one ground extender  170  will now be described with reference to  FIG. 4 . 
       FIG. 4  is a view of a PCB module  430  installable in the antenna apparatus  100 , according to an embodiment of the disclosure. 
       FIG. 4  illustrates three locations A, B, and C where ones of the at least one ground extender  170  may be arranged within the PCB module  430 . 
     There is a ground region  437  within the PCB module  430 , and one of the at least one ground extender  170  may be arranged on the ground region  437  of the PCB module  430 . For example, as shown in  FIG. 4 , the ground extender  170  may be arranged at location A, B, or C within the ground region  437 . 
     Although  FIG. 4  illustrates only three locations where the ones of the at least one ground extender  170  is installable, this is only by way of example, and the at least one ground extender  170  may be installed at a variety of other locations capable of transmitting a current flowing in the ground of the PCB module  430  to the metal panel  20 . 
     The at least one ground extender  170  is connected to the metal panel  20 , at a specific location within the ground region  437 . According to what point of the ground region  437  the at least one ground extender  170  is installed at, a resonance frequency of the antenna apparatus  100  may be changed (see  FIG. 7 ). 
     Accordingly, the at least one ground extender  170  is arranged at at least one location where the antenna apparatus  100  may resonate in a desired frequency band, from among the various locations of the ground region  437 , and thus the antenna apparatus  100  may smoothly collect a broadcasting signal of the frequency band. 
     As shown in  FIG. 4 , a low noise amplifier  439  is connected to a current path connected to the feeding line  150 , and a current amplified by the low noise amplifier  439  is transmitted to a broadcasting receiver. 
       FIG. 5  is graphs comparing radiation characteristics according to presence or absence of the ground extender  170  within the antenna apparatus  100 , and  FIG. 6  is graphs comparing the characteristics of a current in the metal panel  20  of a vehicle according to presence or absence of the ground extender  170  within the antenna apparatus  100 . 
     The left graph of  FIG. 5  indicates a signal reflection coefficient of the antenna apparatus  100 , and the right graph thereof indicates radiation efficiency of a signal. 
     As described above, the antenna apparatus  100  includes the ground extender  170  electrically connecting the ground of the PCB module  130  to the metal panel  20 . As shown in the right graph of  FIG. 5 , when the ground extender  170  is applied, radiation efficiency in a frequency band for receiving broadcasting may be improved, compared when the ground extender  170  is not applied. This is because the ground region extends to the metal panel  20  through the ground extender  170 . 
     As can be seen from the left graph of  FIG. 5 , resonance is the most smoothly achieved at about 0.18 GHz when the ground extender  170  is applied, whereas the antenna apparatus  100  does not resonate at the frequency, namely, about 0.18 GHz, when the ground extender  170  is not applied. 
     When the PCB module  130  is connected to the metal panel  20  by using the ground extender  170 , as shown on the right side of  FIG. 6 , a current flows in the entire car body, and thus radiation efficiency of the antenna is improved. On the other hand, the antenna and the metal panel  20  are capacitively coupled to each other upon non-application of the ground extender  170 , and thus a current is generated only in a portion of the car body around an antenna. 
       FIG. 7  are graphs comparing radiation characteristics according to connection locations of the at least one ground extender  170  within the antenna apparatus  100 . 
       FIG. 7  illustrates radiation characteristics when the at least ground extender  170  is electrically connected to the metal panel  20  at different locations within the ground region of the PCB module  430 . For example, plot A of  FIG. 7  indicates radiation characteristics when the ground extender  170  is arranged at location A of  FIG. 4 , plot B thereof indicates radiation characteristics when the ground extender  170  is arranged at location B of  FIG. 4 , and plot C thereof indicates radiation characteristics when the ground extender  170  is arranged at location C of  FIG. 4 . 
     Referring to the left graph of  FIG. 7 , respective resonance frequencies when the at least one ground extender  170  is arranged at location A, at location B, and at location C are different from one another. 
     Referring to the right graph of  FIG. 7 , when the one of the at least one ground extender  170  is arranged at location A, radiation efficiency is optimal at about 0.23 GHz; when a second of the at least one ground extender  170  is arranged at location B, radiation efficiency is optimal at about 0.21 GHz; and when a third of the at least one ground extender  170  is arranged at location C, radiation efficiency is optimal at about 0.185 GHz. 
     In other words, the resonance frequency of the antenna apparatus  100  may be changed according to at what location on the ground region  437  of the PCB module  430  the at least one ground extender  170  is connected to the metal panel  20 . Accordingly, by selecting an appropriate location from the ground region  437  within the PCB module  430  and making a current flow from the selected location to the metal panel  20  through the at least one ground extender  170 , a broadcasting signal of a desired band could be collected. 
       FIG. 8  is a view of a PCB module  830  that may be included in the antenna apparatus  100 , according to an embodiment of the disclosure. The PCB module  830  includes ground regions A, B, and C. Each of A, B, and C correspond to a particular frequency. That is, when a ground extender located at A, B, or C is connects the ground from the PCB to the metal panel, the corresponding frequency becomes the resonant frequency of the PCB. 
     Accordingly, one of the one or more ground extenders  170  and switch  833   a  is located at ground region A, a second of the one or more ground extenders  170  and switch  833   b  is located a ground region B, and a third of the one or more ground extenders  170  and switch  833   c  is located at ground region C. The control unit  835  can receive a request for a particular resonant frequency and, responsive thereto, selectively shorts one of the switches  833   a ,  833   b , or  833   c.    
     Referring to  FIG. 8 , the PCB module  830  may include a ground region  837 , a control unit  835 , a low noise amplifier  839 , and one or more switches  833   a ,  833   b , and  833   c . The at least one ground extender  170  may be connected to the metal panel  20 , at locations A, B, and C. In other words, one of the at least one ground extender  170  may be connected to the metal panel  20  at location A, a second of the at least one ground extender  170  may be connected to the metal panel  20  at location B, and a third of the at least one ground extender  170  may be connected to the metal panel  20  at location C. In other words, the at least ground extender  170  may be connected to the metal panel  20  at at least one location or at two or more locations at the same time. 
     Referring to  FIG. 8 , the ground of location A where the one of the at least one ground extender  170  may be arranged, the ground of location B where the second of the at least one ground extender  170  may be arranged, and the ground of location C where the third of the at least one ground extender  170  may be arranged are isolated from their neighboring ground regions. In other words, the ground of location A, the ground of location B, and the ground of location C may be isolated from their neighboring ground regions through a fill-cut. Accordingly, a current may be made flow to a desired ground from among the ground of location A, the ground of location B, and the ground of location C through ground switching using a variable diode, an FET device, a BJT device, etc. 
       FIG. 8  illustrates that ground extenders  170  are installed at three different locations within the PCB module  830  and the three switches  833   a ,  833   b , and  833   c  are included in the PCB module  830  to achieve ground switching, but this illustration is merely an example. According to structures of a circuit of the PCB module  830 , the number of ground extenders  170 , the installation location of a ground extender  170 , the number of switches, and the location of a switch may vary. 
     As described above, according to a location on the PCB module  830  where the ground extender  170  is connected to the metal panel  20 , the resonance frequency of the antenna apparatus  100  may vary. According to the embodiment of  FIG. 8 , because the ground extenders  170  are connected to the metal panel  20  at a plurality of different locations, the PCB module  830  may adjust the resonance frequency of the antenna apparatus  100  through ground switching. 
     In other words, when receiving a request to change a frequency from a broadcasting receiver to a target frequency, the control unit  835  of the PCB module  830  may control the switches  833   a ,  833   b , and  833   c  so that a current flows to only a ground extender  170  corresponding to the target frequency to which the frequency is changed from among the ground extenders  170  installed at different locations. A ground extender  170  arranged at a location where no currents flow does not affect the resonance frequency of the antenna apparatus  100 . 
     A passenger may request a frequency change through a frequency control button or frequency control dial connected to the broadcasting receiver, and the broadcasting receiver may transmit a request for a change to the frequency requested by the passenger to the control unit  835  of the PCB module  830 . 
     Describing ground switching in detail with reference to  FIG. 8 , the control unit  835  controls the a switch  833   a  and the b switch  833   b  to be turned off and the c switch  833   c  to be turned on, according to the request to change the frequency, so that a current may flow through location C, in detail, through the ground extender  170  installed at location C. The control unit  835  controls the a switch  833   a  and the c switch  833   c  to be turned off and the b switch  833   b  to be turned on, according to the request to change the frequency, so that a current may flow through location B, in detail, through the ground extender  170  installed at location B. The control unit  835  controls the b switch  833   b  and the c switch  833   c  to be turned off and the a switch  833   a  to be turned on, according to the request to change the frequency, so that a current may flow through location A, in detail, through the ground extender  170  installed at location A. 
     For example, it is assumed that a resonance frequency when a current flows to location B is greater than that when a current flows to location A, and a resonance frequency when a current flows to location C is greater than that when a current flows to location B. In this case, the control unit  835  may control the a switch  833   a  and the c switch  833   c  to be turned off and the b switch  833   b  to be turned on, so that a current flowing to location A flows to location B according to a frequency increasing request from the broadcasting receiver. Alternatively, the control unit  835  may control the a switch  833   a  and the b switch  833   b  to be turned off and the c switch  833   c  to be turned on, so that the current flowing to location B flows to location C according to a frequency increasing request from the broadcasting receiver. 
     According to the PCB module  830  of  FIG. 8 , the resonance frequency may be simply changed through ground switching using the switches  833   a ,  833   b , and  833   c  each composed of a variable device according to the frequency increasing request from the broadcasting receiver. 
     In certain embodiments, the resonant frequency of the PCB can be set using a variable impedance device. 
       FIG. 9  is a view of a PCB module  930  that may be included in the antenna apparatus  100 , according to an embodiment of the disclosure. 
     Referring to  FIG. 9 , the PCB module  930  may include a variable impedance device  934 , a control unit  935 , and a low noise amplifier  939 . 
     At least one ground extender  170  is arranged on the ground region  937 , and is connected to the metal panel  20 . 
     The control unit  935  may receive a request to change a frequency from a broadcasting receiver to a target frequency, and may change the value of the variable impedance device  934  according to a target frequency to which the frequency is changed. The variable impedance device  934  may include at least one of a variable capacitor or a variable inductor. Because the resonance frequency of the antenna apparatus  10  changes with a change in the value of the variable impedance device  934 , the control unit  935  may receive a broadcasting signal of a desired frequency band by changing the value of the variable impedance device  934  according to the target frequency. 
       FIG. 10  is a graph showing radiation characteristics according to the value of the variable impedance device  934  within the antenna apparatus  100 . 
     Referring to  FIG. 10 , respective resonance frequencies when there are no variable impedance devices  934 , when the value of the variable impedance device  934  is 100 nH, and when the value of the variable impedance device  934  is 200 nH may be different from one another. In other words, a broadcasting signal of a band desired by a user could be collected, by adjusting the value of the variable impedance device  934  included in the PCB module  930 . 
     In certain embodiments, the resonant frequency of the PCB can be set by adjusting the gap between the antenna  110  and the metal panel  20  using a lifting module  190 . 
       FIG. 11  is a schematic view of an antenna apparatus  1100  according to another embodiment of the disclosure. 
     Referring to  FIG. 11 , the antenna apparatus  1100  may include the antenna  110 , the feeding line  150 , the PCB module  130 , the ground extender  170 , and a lifting module  190 . 
     The antenna  110  collects a broadcasting signal that is broadcast from a broadcasting station. The antenna  110  may convert electromagnetic waves corresponding to the broadcasting signal into a current. The antenna  110  may include a monopole antenna, a dipole antenna, a loop antenna, or a slot antenna. 
     The PCB module  130  is electrically connected to the antenna  110  through the feeding line  150 , receives the current, filters, demodulates, and amplifies the current, and transmits a signal to a broadcasting receiver. According to an embodiment of the disclosure, the PCB module  130  may include a tuner that matches an impedance of the broadcasting receiver with an impedance of the antenna  110 . The ground extender  170  electrically connects a ground of the PCB module  130  to the metal panel  20  of a vehicle. In detail, one end of the ground extender  170  contacts the ground of the PCB module  130  and the other end thereof contacts the metal panel  20 , and thus the ground of the PCB module  130  and the metal panel  20  may be electrically connected to each other. The ground extender  170  may include a conductive material (for example, metal). 
     The lifting module  190  adjust a gap d between the antenna  110  and the metal panel  20  by adjusting the height of the antenna  110 . The lifting module  190  may adjust the height of the antenna  110  by performing the adjustment at the lateral surface of the antenna  110  as shown in  FIG. 11 , but this is merely an example. The lifting module  190  may adjust the height of the antenna  110  while supporting a lower surface of the antenna  110 . In other words, the lifting module  190  may have one of various structures capable of adjusting the height of the antenna  110 . 
     The antenna  110  and the metal panel  20  perform capacitive coupling, and, according to the capacitive coupling, a current generated in one of the antenna  110  and the metal panel  20  causes an induced current in the other. When the gap d between the antenna  110  and the metal panel  20  is changed, capacitance between the antenna  110  and the metal panel  20  is changed, and accordingly, the resonance frequency of the antenna apparatus  1100  may also be changed. 
     The lifting module  190  may receive a request to change a frequency from a broadcasting receiver, and may adjust the gap d between the antenna  110  and the metal panel  20  so that the antenna apparatus  1100  may resonate at a target frequency to which the frequency is changed. As will be described later with reference to  12 , the resonance frequency increases with a decrease in the gap d between the antenna  110  and the metal panel  20 , and thus the lifting module  190  may raise the antenna  110  according to a frequency increasing request from the broadcasting receiver, and conversely may lower the antenna  110  according to a frequency decreasing request from the broadcasting receiver. 
       FIG. 12  is a graph showing radiation characteristics of the antenna apparatus  1100  according to a gap between the antenna  110  and the metal panel  20 . 
     Referring to  FIG. 12 , respective resonance frequencies when the gap between the antenna  110  and the metal panel  20  is 15 mm, when the gap therebetween is 25 mm, and when the gap therebetween is 35 mm may be different from one another. In other words, a broadcasting signal of a band desired by a user could be collected, by the lifting module  190  adjusting the height of the antenna  110 . 
       FIG. 13  is a schematic view of an antenna apparatus  1300  according to another embodiment of the disclosure. 
     Referring to  FIG. 13 , the antenna apparatus  1300  may include the antenna  110 , the feeding line  150 , the PCB module  130 , the ground extender  170 , and a dielectric panel  120 . 
     The antenna  110  collects a broadcasting signal that is broadcast to a broadcasting station. The antenna  110  may convert electromagnetic waves corresponding to the broadcasting signal into a current. The antenna  110  may include a monopole antenna, a dipole antenna, a loop antenna, or a slot antenna. 
     The PCB module  130  is electrically connected to the antenna  110  through the feeding line  150 , receives the current corresponding to the broadcasting signal from the antenna  110 , filters and amplifies the current, and transmits a result of the filtering and the amplification to a broadcasting receiver. 
     The ground extender  170  electrically connects a ground of the PCB module  130  to the metal panel  20  of a vehicle. 
     The dielectric panel  120  is located between the antenna  110  and the metal panel  20 . The dielectric panel  120  is provided to adjust the capacitance of a space between the antenna  110  and the metal panel  20 . As described above, because the antenna  110  and the metal panel  20  perform capacitive coupling, when the capacitance of the space between the antenna  110  and the metal panel  20  is changed, the resonance frequency of the antenna apparatus  1300  is also changed. In other words, the dielectric panel  120  may be located between the metal panel  20  and the antenna  110  such that the antenna apparatus  1300  may resonate at a frequency desired by a passenger. 
       FIG. 14  is a flowchart of a method of receiving broadcasting by the antenna apparatus  100 , according to an embodiment of the disclosure. 
     In operation S 1410 , the antenna apparatus  100  installed below the metal panel  20  of vehicle  10  collects a broadcasting signal radiated by a broadcasting station, and converts the broadcasting signal into a current. The broadcasting signal may be collected by the antenna  110  included in the antenna apparatus  100 . 
     In operation S 1420 , the PCB module  130  transmits the current obtained by the antenna  110  and amplifies the current. In operation S 1430 , the PCB module  130  transmits an amplified current to a broadcasting receiver. 
     The broadcasting receiver outputs the amplified current as visual data or audio data through a monitor, a speaker, or the like. 
     As described above, the ground of the PCB module  130  is electrically connected to the metal panel  20  through the ground extender  170 . 
     The PCB module  130  may receive a request to change a frequency from the broadcasting receiver, and may control a switch so that a current flows to a location corresponding to a target frequency to which the frequency is changed from among the different locations within the ground region where the ground extenders  170  are arranged, thereby collecting a broadcasting signal of a desired band. 
     The PCB module  130  may receive a request to change a frequency from the broadcasting receiver, and may change the value of a variable impedance device located on a current path according to the target frequency to which the frequency is changed, thereby changing the resonance frequency of the antenna apparatus  100 . 
     According to an embodiment, the antenna apparatus  100  may further include the lifting module  190  to adjust the height of the antenna  110 . In this case, a control unit (for example, a central processing unit) included in the lifting module  190  may receive a request to change a frequency from the broadcasting receiver, and may adjust a gap between the metal panel  20  and the antenna  110  according to the target frequency to which the frequency is changed, thereby changing the resonance frequency of the antenna apparatus  100 . 
     The above-described embodiments may be stored as a program in a machine-readable storage medium. The machine-readable storage medium may be provided as a non-transitory storage medium. Here, the ‘non-transitory storage medium’ is a tangible device and means that the storage medium does not include a signal (for example, electromagnetic waves), but this term does not distinguish whether data is stored semi-permanently or temporarily in the storage medium. For example, the ‘non-transitory storage medium’ may include a buffer that temporarily stores data. 
     According to an embodiment, methods according to the various disclosed embodiments of the disclosure may be provided by being included in a computer program product. The computer program product may be traded as a commodity between a seller and a purchaser. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed online (e.g., download or upload) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). When distributed online, at least part of the computer program product (e.g., a downloadable app) may be temporarily generated or at least temporarily stored in a machine-readable storage medium, such as a memory of a manufacturer&#39;s server, a server of the application store, or a relay server. 
     In an antenna apparatus for vehicles and a method of receiving broadcasting by using the antenna apparatus, according to an embodiment of the disclosure, the antenna apparatus is not exposed to the outside of vehicles. 
     In the antenna apparatus for vehicles and the method of receiving broadcasting by using the antenna apparatus, according to an embodiment of the disclosure, the antenna apparatus may have an improved radiation capability due to extension of the ground of a PCB module connected to an antenna. 
     In the antenna apparatus for vehicles and the method of receiving broadcasting by using the antenna apparatus, the antenna apparatus is able to receive broadcasting signals of various frequencies. 
     However, effects attainable by the antenna apparatus for vehicles and the method of receiving broadcasting by using the antenna apparatus according to an embodiment of the disclosure are not limited to the aforementioned effects, and other effects not mentioned above will be clearly understood by one of ordinary skill in the art from the description below, 
     While one or more embodiments of the disclosure have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.