KR20230171666A - Microstrip traveling-wave series-fed array antennas and design method thereof - Google Patents

Abstract

The present invention provides a design method for compensating for phase offset while ensuring in-phase radiation and determining the distance between antenna elements that can be applied to both patch and comb-line types, and a design method thereof. It relates to a technology for providing a designed microstrip traveling wave serial feed array antenna. According to one embodiment of the present invention, a first antenna element, an N-th antenna element, and an N+1-th antenna are interconnected by transmission lines. The method of designing a microstrip traveling wave serial feed array antenna including an antenna element includes the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+) of the N+1 antenna element. ₁ ) determining a distance (d _n ) between the N-th antenna element and the N+1-th antenna element, considering the N-th antenna element and the N+1-th antenna according to the determined distance (d _n ) Determining coupling efficiency by considering power loss (P _loss,n ) between elements and arranging the first antenna element, the N-th antenna element, and the N+1-th antenna element based on the determined coupling efficiency. may include.

Description

Microstrip traveling wave serial feed array antenna and its design method {MICROSTRIP TRAVELING-WAVE SERIES-FED ARRAY ANTENNAS AND DESIGN METHOD THEREOF}

The present invention relates to a microstrip traveling wave serial feed array antenna and its design method. More specifically, it compensates for phase offset while ensuring in-phase radiation, and applies to both patch and comb-line types. This is a technology for providing a design method for determining the distance between antenna elements and a microstrip traveling wave serial feed array antenna designed by the design method.

Microstrip traveling wave serial feed array antennas have been developed for radar systems in the millimeter wave band.

Microstrip traveling wave serially fed array antennas have received much attention for weather radar, automotive radar, and wireless communication systems.

The series connection of microstrip traveling wave serial feed array antennas is used as a small feed line with low loss and high efficiency.

The microstrip traveling wave serial feed array antenna can provide a wider bandwidth than the resonant antenna based on the non-resonant function of the traveling wave antenna.

However, microstrip traveling wave serially fed array antennas combine antenna elements for a smooth and tapered amplitude profile, such as a Taylor or Dolph-Chebyshev distribution for low sidelobe level (SLL). The efficiency, i.e. the ratio of input power to radiated power, must cover a wide range.

In a microstrip traveling wave serial feed array antenna, the phase of each element can affect each other as the signal moves.

A common way to control the phase in a series-fed array antenna is to adjust the distance between antenna elements. In a combline array antenna according to the prior art, the distance of the elements is the transmission coefficient phase of the antenna device minus the phase delay from the input to the output line. Adjusted to compensate for (∠S21).

However, this method has the disadvantage of not being able to guarantee an in-phase far field for the broadside beam because it only considers the signal phase delay, not the antenna's radiation phase.

Microstrip traveling wave serially fed array antennas are connected and fed in series in an array topology.

Therefore, it is difficult for the microstrip traveling wave serial feed array antenna to excite an antenna element with an appropriately tapered true width and in-phase for a broadside beam with a low SLL.

In serial feeding patch and combline array antennas where the distance between array antenna elements is set according to the prior art, in-phase radiation is not guaranteed, so it is necessary to optimize the distance between array antenna elements.

Korean Patent Publication No. 10-2021-0062574, “Capacitive Coupled Combline Microstrip Array Antenna” Korean Patent Publication No. 10-2020-0110069, “Microstrip array antenna” Korean Patent No. 10-2007876, “Microstrip array antenna”

The present invention provides a design method for compensating for phase offset while ensuring in-phase radiation and determining the distance between antenna elements that can be applied to both patch and comb-line types, and a design method thereof. The purpose is to provide a designed microstrip traveling wave serial feed array antenna.

The purpose of the present invention is to provide a design method for a microstrip traveling wave serial feeding array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of the microstrip traveling wave serial feeding array antenna.

The purpose of the present invention is to provide a design method for a microstrip traveling wave serial feed array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of patch array antennas and combline array antennas. .

According to an embodiment of the present invention, the method of designing a microstrip traveling wave serial feed array antenna including a first antenna element, an N-th antenna element, and an N+1-th antenna element interconnected by transmission lines is provided by the first antenna element. Considering the transmission coefficient phase (∠S _21,1 ) of the antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element, the N-th antenna element and the N+1-th antenna element Determining the distance (d _n ) between the N-th antenna element and the N+1-th antenna element according to the determined distance (d _n ), determining the coupling efficiency by considering the power loss (P _loss,n ) between the N-th antenna element and the N+1-th antenna element. It may include arranging the first antenna element, the Nth antenna element, and the N+1th antenna element based on the determined coupling efficiency.

Considering the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element, the Nth antenna element and the N+ 1 The step of determining the distance (d _n ) between antenna elements includes the length of the output transmission line of the Nth antenna element (L _out,n ), the length of the input transmission line of the N+1th antenna element (L _{in, n+1} ), guided wavelength of the transmission lines (λ _g ), phase of radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), radiation in the reference direction of the N antenna element Using the phase of the field (∠E _r,n ), the transmission coefficient phase of the first antenna element (∠S _21,1 ) to the transmission coefficient phase of the N+1 antenna element (∠S _21,n+1 ) It may include determining the distance (d _n ).

According to one embodiment of the present invention, the method of designing a microstrip traveling wave serial feed array antenna includes the steps of adjusting the size of an inserted slit with respect to the width (W) and length (L) of the transmission lines, the first antenna element , the width (W _s ) and length (L _s ) of the square-shaped cut applied to the width (W) and length (L) of each of the N-th antenna element and the N+1-th antenna element. It may further include adjusting the distance between any one of the transmission lines and the center of each of the first antenna element, the Nth antenna element, and the N+1th antenna element. .

The step of adjusting the size of the inserted slit with respect to the width (W) and length (L) of the transmission lines includes the length (L _slit ) and width (W _slit ) of the slit depending on the size of the adjusted slit. And it may include reducing reflection at the input port of the transmission line by adjusting the distance (D _slit ) from the edge of the antenna element to the slit.

Adjusting the width (W s ) and length (L _s ) of the square cut applied to the width (W) and length (L) of each of the first antenna element, the N-th antenna element, and the N _+1-th antenna element. The step is to adjust the reflection loss according to the width (W) of each of the first antenna element, the Nth antenna element, and the N+1 antenna element at the input side of the transmission lines (W _s ). It may include the step of adjusting the length (L _s ).

The step of adjusting the distance between any one of the transmission lines and the centers of each of the first antenna element, the Nth antenna element, and the N+1th antenna element is based on the adjusted distance between the centers. It may include adjusting the coupling induction to radiated power and adjusting the coupling efficiency based on the adjusted coupling induction.

According to one embodiment of the present invention, the method of designing a microstrip traveling wave serial feed array antenna includes the steps of adjusting the size of an inserted slit with respect to the width (W) and length (L) of the transmission lines, the first antenna element , adjusting the width (W _e ) of each of the Nth antenna element and the N+1th antenna element, and adding a stub to each of the first antenna element, the Nth antenna element, and the N+1th antenna element. It may further include adjusting the length (L _s ) and width (W _s ) of the added stub, the distance (g) between the added stubs, and the distance (D) connected at the end.

The step of adjusting the width (W _e ) of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element includes adjusting the signal and radiation path according to the adjusted width (W _e ). It may include adjusting the coupling efficiency by adjusting the length of the input transmission line (L _in ) and the phase of the radiation field (∠E _r ) in the reference direction for a transmission coefficient phase (∠S ₂₁ ) close to 0". .

A stub is added to each of the first antenna element, the Nth antenna element, and the N+1th antenna element, and the length (L _s ) and width (W _s ) of the added stub, and the distance between the added stub and the added stub, The step of adjusting the gap (g) and the distance (D) connected from the end is to adjust the coupling efficiency by adjusting the phase (∠E _r ) of the radiation field in the reference direction by adjusting the size of the width (W _s ). May include steps.

The first antenna element, the Nth antenna element, and the N+1th antenna element may be any one of a patch serial feed array antenna element and a combline serial feed array antenna element.

According to an embodiment of the present invention, the microstrip traveling wave serial feed array antenna includes a first antenna element, an N-th antenna element, and an N+1-th antenna element that are interconnected by transmission lines, and the N-th antenna element and the N+1 antenna element is based on the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element. A distance (d _n ) between the N-th antenna element and the N+1-th antenna element is determined, and a power loss (P) between the N-th antenna element and the N+1-th antenna element according to the determined distance (d _n ). The coupling efficiency is determined by considering _{the loss,n} ), and can be arranged together with the first antenna element based on the determined coupling efficiency.

The distance (d _n ) between the Nth antenna element and the N+1th antenna element is the length of the output transmission line of the Nth antenna element (L _out,n ), and the length of the input transmission line of the N+1th antenna element. Length (L _in,n+1 ), guided wavelength of the transmission lines (λ _g ), phase of the radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), and the N antenna element Phase of the radiation field in the reference direction (∠E _r,n ), transmission coefficient phase of the first antenna element (∠S _21,1 ) to transmission coefficient phase of the N+1 antenna element (∠S _{21,n+ 1} ) can be determined using.

The first antenna element, the Nth antenna element, and the N+1th antenna element may be any one of a patch serial feed array antenna element and a combline serial feed array antenna element.

The present invention provides a design method for compensating for phase offset while ensuring in-phase radiation and determining the distance between antenna elements that can be applied to both patch and comb-line types, and a design method thereof. A designed microstrip traveling wave serial feed array antenna can be provided.

The present invention can provide a design method for a microstrip traveling wave serial feed array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of the microstrip traveling wave serial feed array antenna.

The present invention can provide a design method for a microstrip traveling wave serial feed array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of patch array antennas and combline array antennas.

1A to 1C are diagrams illustrating a general-purpose design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.
Figure 2 is a diagram illustrating coupling efficiency between antenna elements according to power flow of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.
3A to 3C are diagrams illustrating a design method of a patch array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention.
FIGS. 4A to 4D are diagrams illustrating the characteristics of a microstrip traveling wave serial feed array antenna according to a design method of a patch array antenna according to an embodiment of the present invention.
Figures 5a and 5b are diagrams illustrating a design method of a comb line array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention.
6A to 6C are diagrams illustrating the characteristics of a microstrip traveling wave serial feed array antenna according to a design method of a comb line array antenna according to an embodiment of the present invention.
7A and 7B are diagrams illustrating a patch array antenna and a comb line array antenna according to an embodiment of the present invention.
Figures 8A to 8C are diagrams explaining the characteristics of a patch array antenna and a comb line array antenna according to an embodiment of the present invention.
9A and 9B are diagrams illustrating simulation results of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.
Figure 10 is a diagram illustrating a design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are merely illustrative for the purpose of explaining the embodiments according to the concept of the present invention. They may be implemented in various forms and are not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention can make various changes and have various forms, the embodiments will be illustrated in the drawings and described in detail in this specification. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes changes, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms such as first or second may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component, for example, a first component may be named a second component, without departing from the scope of rights according to the concept of the present invention, Similarly, the second component may also be referred to as the first component.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between. Expressions that describe the relationship between components, such as “between”, “immediately between” or “directly adjacent to”, should be interpreted similarly.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of implemented features, numbers, stages, operations, components, parts, or combinations thereof, as well as one or more other features or numbers, It should be understood that this does not exclude in advance the possibility of the presence or addition of stages, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings they have in the context of the related technology, and unless clearly defined in this specification, should not be interpreted in an idealized or overly formal sense. No.

1A to 1C are diagrams illustrating a general-purpose design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Figure 1a illustrates a radiating element configuration with input and output ports in relation to a microstrip traveling wave serial feed array antenna, Figure 1b illustrates a patch antenna element as a microstrip traveling wave serial feed array antenna, and Figure 1c shows a microstrip traveling wave serial feed array antenna. A combline antenna element is illustrated as a series feed array antenna.

The general design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention illustrates a general design equation for determining the optimal distance between antenna elements using the definitions shown in each drawing.

Referring to FIG. 1A, the radiating element 100 has an input port 101 and an output port 102, and the input port 101 and the output port 102 are connected to a transmission line.

The transmission line connected to the input port 101 may be an input transmission line, and the transmission line connected to the output port 102 may be an output transmission line.

According to one embodiment of the present invention, the radiating element 100 may be an antenna unit model, and the transmission coefficient phase (∠S ₂₁ ) from the input port 101 including the antenna structure to the output port 102 and the phase of the radiated field at boresight (∠E _r ) in the reference direction.

Referring to FIG. 1B, the patch array antenna includes an Nth patch antenna element 110 and an N+1th patch antenna element 111.

Referring to FIG. 1C, the combline array antenna includes an Nth patch antenna element 120 and an N+1th patch antenna element 121.

In relation to the Nth patch antenna element 110, the N+1th patch antenna element 111, the Nth patch antenna element 120, and the N+1th patch antenna element 121, separate input and output lines are provided. Define parameters.

With respect to patch antenna elements, the length of the input transmission line associated with the input line (L _in ) represents the physical length from the input port to the beginning of the radiating element, and the length of the output transmission line associated with the output line (L _out ) represents the physical length from the input port to the beginning of the radiating element. It can represent the physical length from the end of the radiating element to the output port. Here, the radiating element may be referred to as a patch antenna element.

With respect to a combline antenna element, the edges of the radiating element indicated by dotted lines simultaneously indicate the start and end of the radiating element. Here, the radiating element may be referred to as a comb line antenna element.

The distance (dn) between the Nth patch antenna element 110 and the N+1th patch antenna element 111 is the length (L _out,n ) of the output transmission line of the Nth patch antenna element 110 and the N+th patch antenna element 110. 1 It can be defined as the sum of the lengths (L _in,n+1 ) of the input transmission line of the patch antenna element 111.

The distance (dn) between the Nth patch antenna element 120 and the N+1th patch antenna element 121 is the length (L _out,n ) of the output transmission line of the Nth patch antenna element 120 and the N+th patch antenna element 120. 1 It can be defined as the sum of the lengths (L _in,n+1 ) of the input transmission line of the patch antenna element 121.

According to the prior art, it is difficult to ensure in-phase radiation when a microstrip traveling wave feed array antenna accommodates a phase delay in relation to the transmission coefficient phase between antenna elements.

According to one embodiment of the present invention, the microstrip traveling wave serial feed array antenna can compensate for phase offset while ensuring in-phase radiation by adjusting the distance between the antenna elements constituting the antenna based on Equation 1 below.

[Equation 1]

In Equation 1, d _n may represent the distance between the Nth antenna element and the N+1th antenna element, L _out,n may represent the length of the output transmission line of the Nth antenna element, L _{in, n+1} may represent the length of the input transmission line of the N+1 antenna element, λ _g may represent the induced wavelength of the transmission lines, and ∠E _r,n+1 is the standard of the N+1 antenna element. It can represent the phase of the radiation field in the direction, ∠E _r,n can represent the phase of the radiation field in the reference direction of the Nth antenna element, and ∠S _21,1 can represent the transmission coefficient phase of the first antenna element, , ∠S _21,n+1 can represent the transmission coefficient phase of the N+1th antenna element, and ∠S _21,1 ^~ ∠S _21,n+1 is combined from the first antenna element to the N+1th antenna element. It can represent the transmission coefficient phase of the antenna element.

For example, the first antenna element may refer to the first antenna element constituting the microstrip traveling wave serial feed array antenna.

The design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention uses Equation 1 to sequentially calculate the distance (d _n ) while changing the number applied to n to determine the distance between arrayed antenna elements. By applying it to calculate the optimal distance to the in-phase radiation field in the reference direction without iterative optimization, the microstrip traveling wave serial feed array antenna can be designed as a patch serial feed array antenna or a combline serial feed array antenna.

The design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention uses Equation 1 to calculate the length (L _out,n ) of the output transmission line of the Nth antenna element and the input of the N+1th antenna element. Length of the transmission line (L _in,n+1 ), guided wavelength of the transmission lines (λ _g ), phase of the radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), N antenna element Phase of the radiation field in the reference direction (∠E _r,n ), transmission coefficient phase of the first antenna element (∠S _21,1 ) to transmission coefficient phase of the N+1 antenna element (∠S _21,n+1 ) The distance (d _n ) between the Nth antenna element and the N+1th antenna element based on can be determined.

Figure 2 is a diagram illustrating coupling efficiency between antenna elements according to power flow of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Figure 2 illustrates the power flow of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Referring to FIG. 2, the microstrip traveling wave serial feed array antenna according to an embodiment of the present invention is a combline array antenna and includes an Nth antenna element 200 and an N+1th antenna element 201.

With respect to the Nth antenna element 200 and the N+1th antenna element 201, P _in , P _out , and P _rad are defined as the input, output, and radiation power of the n or n+1th antenna element, and are defined as the input, output, and radiation power of the Nth antenna element. A simple relationship based on the element 200 is as shown in Equation 2 below.

[Equation 2]

The coupling efficiency (C _n ) can be determined as the ratio of radiated power to the input power of the nth antenna element, and can be expressed as Equation 3 below.

[Equation 3]

In order to achieve combination efficiency, the input power (P _in,n+1 ) of the N+1th antenna element 201 is divided into the Nth antenna element 200 and the N+1th antenna element (P in,n+1) based on Equations 2 and 3. 201), it can be calculated as in Equation 4 below, considering the power loss (P _loss,n ) and the output power (P _in,n ) of the Nth antenna element 200.

[Equation 4]

According to one embodiment of the present invention, the relative excitation amplitude (a n ) of each element of the comb line array antenna, the Nth antenna element 200 and the N+1th antenna element ₂₀₁ , can be converted as shown in Equation 5 below. You can.

[Equation 5]

According to one embodiment of the present invention, the design method of the microstrip traveling wave serial feed array antenna is the power loss (P _loss) between the Nth antenna element and the N+1th antenna element according to the distance (d _n ) determined based on Equation 1. By considering _,n ), the combining efficiency can be determined.

Therefore, the present invention provides a design method for a microstrip traveling wave serial feed array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of the patch array antenna and the combline array antenna. .

3A to 3C are diagrams illustrating a design method of a patch array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention.

3A to 3C show first to third types of patches for achieving a wide range of coupling efficiency with a low reflection coefficient according to a design method of a patch array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention. An antenna element is illustrated.

Referring to FIG. 3A, the first type of antenna element 300 has a first port 301 and a second port 302, is a general patch antenna element, and has the length (L _p ) and width (W _{p )} of the patch. ) was fixed to minimize input reflections at 76.5 GHz.

In addition, the first type of antenna element 300 adjusts the length of the input transmission line (L _in ) and the length of the output transmission line (L _out ) so that the transmission coefficient phase (∠S ₂₁ ) is “0”.

Referring to FIG. 3B, the second type of antenna element 310 is a patch antenna element that has a first port 311 and a second port 312 and has increased coupling efficiency by inserting a slit. The length (L _p ) and width (W _p ) are 1.3 mm to 1.6 mm, fixed to minimize input reflections at 76.5 GHz, and a square-shaped cut on the output side with length (L _s ) and width (W _s ). was inserted, and a slit with length (L _slit ) and width (W _slit) was added to the input side to reduce input reflection, and its position is determined by D _slit , the distance between the slit and the patch.

Add slits to the input transmission line only if the length (L _s ) and width (W _s ) are greater than 0.3 mm.

Referring to FIG. 3B, the second type of antenna element 310 is a patch antenna element that has a first port 311 and a second port 312 and has increased coupling efficiency by inserting a slit. The length (L _p ) and width (W _p ) are 1.3 mm to 1.6 mm, fixed to minimize input reflections at 76.5 GHz, and a square-shaped cut on the output side with length (L _s ) and width (W _s ). was inserted, and a slit with length (L _slit ) and width (W _slit) was added to the input side to reduce input reflection, and its position is determined by D _slit , the distance between the slit and the patch.

Add slits to the input transmission line only if the length (L _s ) and width (W _s ) are greater than 0.3 mm.

Referring to FIG. 3C, the third type of antenna element 320 has a first port 321 and a second port 322, and a slit is inserted to increase coupling efficiency, thereby increasing the coupling efficiency between the patch and the output line. It is a patch antenna element in which a gap (g) is inserted, and the length (L _p ) and width (W _p ) of the patch are 1.3 mm to 1.6 mm, fixed to minimize input reflection at 76.5 GHz, and between the patch and the output line. The spacing (g) is adjusted from 0.1 mm to 0.15 mm, and the distance (D _p ) between the output line and the patch is fixed.

Additionally, for low reflection loss according to the width (W _p ) on the input line, square-shaped cuts were inserted on the output side with length (L _s ) and width (W _s ).

According to one embodiment of the present invention, the second type of antenna element 310 and the third type of antenna element 320 have a slit length (L _slit ), a width (W _slit ), and an antenna according to the size of the slit to be adjusted. By adjusting the distance (D _slit ) from the edge of the device to the slit, reflection at the input port of the transmission line can be reduced.

In addition, the width (W s ) and length (L _s ) of the second type antenna element 310 and the third type antenna element 320 are adjusted to adjust the reflection loss according to each width (W ₎ . The width (W _s ) and length (L _s ) of the square cut are adjusted.

FIGS. 4A to 4D are diagrams illustrating the characteristics of a microstrip traveling wave serial feed array antenna according to a design method of a patch array antenna according to an embodiment of the present invention.

Figure 4a illustrates antenna characteristics when the microstrip traveling wave serial feed array antenna according to the design method of the patch array antenna according to an embodiment of the present invention is a first type of patch array antenna.

Figure 4b illustrates antenna characteristics when the microstrip traveling wave serial feed array antenna according to the design method of the patch array antenna according to an embodiment of the present invention is a second type of patch array antenna.

Figure 4c illustrates antenna characteristics when the microstrip traveling wave serial feed array antenna according to the design method of the patch array antenna according to an embodiment of the present invention is a third type of patch array antenna.

Figure 4d illustrates the characteristics of the antenna when the first to third type patch antenna elements according to the design method of the patch array antenna according to an embodiment of the present invention are used in combination.

Graph 400 shows L _in and ∠E _r of the first type of antenna element at 76.5 GHz with changes in the width (W _P ) of the antenna element from 0.4 mm to 1.3 mm.

A larger width (W _P ) requires a lower L _in to maintain ∠S ₂₁ close to zero and leads to a higher ∠E _r at boresight.

This indicates that a larger width (W _P ) leads to more signal propagation and less radiation delay.

The graph 410 shows that as the width (W _s ) and width (W _p ) increase, L _in decreases and ∠E _r increases.

It also shows that the cut size (W _s ) in the output transmission line has a greater effect on L _in and ∠E _r than the width (W _p ) of the patch antenna.

Graph 420 shows that the ∠E _r of the third type of antenna element is lower than that of the other types because the current path for radiation in the output cross-section increases.

The fact that the spacing (g) has a minor effect on ∠E _r confirms this inference.

Instead, spacing (g) and width (W _p ) can affect L _in , which is primarily determined by the signal propagation path inside the antenna.

The graph 430 shows the characteristics of the first type 431, the second type 432, and the third type 433.

The coupling efficiency of the first type 431 is indicated by a black solid line, and as the width (W _p ) increases, the efficiency increases within a limited range of 0.6% to 7.3%.

The coupling efficiency of the second type 432 increases compared to the first type 431 from 8.4% to 66.6%.

The coupling efficiency of the third type 433 is that the larger the gap (g), the more coupling it induces to the radiated power, and the third type 433 with the same width (W _P ) range of the second type 432 is 53.4%. It shows that it contains the highest binding efficiency up to 75.7%.

Figures 5a and 5b are diagrams illustrating a design method of a comb line array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention.

5A and 5B are diagrams of a first type and a second type for achieving a wide range of coupling efficiency with a low reflection coefficient according to a design method of a combline array antenna among microstrip traveling wave serial feed array antennas according to an embodiment of the present invention. A combline antenna element is illustrated.

For example, the first and second types of combline antenna elements have rounded corners to prevent main beam tilting and high SLL due to manufacturing errors.

The slit width (W _slit )¸ length (L _slit ) and distance (D _slit ) can be modified appropriately to reduce reflections at the input port.

Referring to FIG. 5A, the first type of comb line antenna element 500 is a typical comb line antenna element, and the length L _e of the radiating element from the corner and the width of the antenna element can be adjusted to suit the input port. Then L _in and L _out can be adjusted by the same number to keep ∠S21 at “0”.

Referring to FIG. 6B, the second type of comb line antenna element 510 uses a circular stub-integrated antenna element, and here, a stub is added to the input of the radiating element with the sub-feed line.

The length (L _s ) and width (W _s ) of the stub, the gap between the stub and the radiator (g), and the distance connected to the end of the element (D) are further adjusted, and L and L _e are the first type of comb line. It may be the same as the antenna element 500.

6A to 6C are diagrams illustrating the characteristics of a microstrip traveling wave serial feed array antenna according to a design method of a comb line array antenna according to an embodiment of the present invention.

Figure 6a illustrates antenna characteristics when the microstrip traveling wave serial feed array antenna according to the design method of the combline array antenna according to an embodiment of the present invention is a first type of combline array antenna.

Figure 6b illustrates antenna characteristics when the microstrip traveling wave serial feed array antenna according to the design method of the combline array antenna according to an embodiment of the present invention is a second type of combline array antenna.

Figure 6c illustrates the characteristics of the antenna when the first type and the second type patch antenna elements according to the design method of the comb line array antenna according to an embodiment of the present invention are used in combination.

The graph 600 shows L _in and ∠E _r of the first type combline antenna element at 76.5 GHz, and the change in W _e is from 0.1 mm to 1.0 mm.

A wider W _e shortens the signal and radiation path, producing a longer L _in and larger ∠E _r for ∠S ₂₁ which is close to zero.

In the graph 610, the wider W _s , the larger ∠E _r , and the wider W _e , the longer L _in and the lower ∠E _r .

Stub-integrated elements have more phase delay as W _s increases, but we can cancel out that delay.

The graph 620 shows the coupling efficiency of the first type 621 and the second type 622. The coupling efficiency of the first type 621 combline antenna element increases as the excitation gradually increases, from 2.3%. It covers a range of 26.8%.

Meanwhile, for the second type (622) combline antenna element, W _s has a greater effect on coupling efficiency than W _e , and the highest coupling efficiency ranges from 32.4% to 91.1%.

7A and 7B are diagrams illustrating a patch array antenna and a comb line array antenna according to an embodiment of the present invention.

Figure 7a illustrates a patch array antenna designed through a microstrip traveling wave serial feed array antenna design method according to an embodiment of the present invention, and Figure 7b illustrates a microstrip traveling wave serial feed array antenna design method according to an embodiment of the present invention. An example of a comb line array antenna designed through .

Referring to FIG. 7A, the patch array antenna 700 according to an embodiment of the present invention is composed of 10 patch antenna elements (a ₁ to a ₁₀ ).

Here, 10 patch antenna elements (a ₁ to a ₁₀ ) are a patch antenna element of the first type 701 described in FIG. 3A, a patch antenna element of the second type 702 described in FIG. 3B, and a patch antenna element of the second type 702 described in FIG. 3C. It consists of a patch antenna element of the described third type (703) and a last patch antenna element (704).

For example, the first antenna element is the first patch antenna element (a ₁ ), the N-th antenna element is the second patch antenna element (a ₂ ), and the N+1-th antenna element is the third patch antenna element (a ₃ ), the microstrip traveling wave serial feed array antenna design method according to an embodiment of the present invention can determine the distance (d ₂ ) between the second patch antenna element (a ₂ ) and the third patch antenna element (a3). .

The parameters of each antenna element of the patch antenna for in-phase excitation can be summarized in Table 1 below.

n type
mm L _{in, n}
deg. ∠E _r,n
deg. ∠S _21,n
deg. ∠S _21,1~n+1
deg. One One 0.64 172.13 0.18 0 2 One 0.62 176.87 0.63 14.4 3 2 0.54 192.15 0.46 14.9 4 2 0.51 192.85 0.43 15.0 5 2 0.38 190.24 0.12 14.7 6 2 0.37 191.31 -0.03 16.6 7 2 0.36 191.96 -0.86 15.4 8 3 0.53 143.07 -0.71 18.1 9 3 0.49 142.96 -0.17 21.5 10 last 0.72 965.59 0 0

Referring to FIG. 7B, the comb line array antenna 710 according to an embodiment of the present invention is composed of 10 comb line antenna elements (a ₁ to a ₁₀ ).

Here, the ten comb line antenna elements (a ₁ to a ₁₀ ) are a comb line antenna element of the first type 711 illustrated in FIG. 5A, a comb line antenna element of the second type 712 illustrated in FIG. 5B, and It consists of the last comb line antenna element 713.

For example, the first antenna element is the first comb line antenna element (a ₁ ), the Nth antenna element is the second comb line antenna element (a ₂ ), and the N+1 antenna element is the third comb line antenna. If the element (a ₃ ), the microstrip traveling wave serial feed array antenna design method according to an embodiment of the present invention is the distance between the second comb line antenna element ( a ₂ ) and the third comb line antenna element (a 3 ) (d ₂ ) can be determined.

Therefore, the present invention provides a design method for compensating for phase offset while ensuring in-phase radiation and determining the distance between antenna elements that can be applied to both patch and comb-line types, and the design method thereof. A microstrip traveling wave serial feed array antenna designed by can be provided.

The parameters of each antenna element of the combline antenna for in-phase excitation can be summarized in Table 2 below.

n type
mm L _{in, n}
deg. ∠E _r,n
deg. ∠S _21,n
deg. ∠S _21,1~n+1
deg. One One 1.37 82.06 0.11 0 2 One 1.39 95.58 0.09 14.05 3 One 1.42 114.67 -0.22 15.64 4 One 1.43 127.01 0.05 16.01 5 2 1.4 78.4 0.11 12.74 6 2 1.41 72.84 -0.11 16.08 7 2 1.44 78.95 0.06 14.55 8 2 1.4 91.87 -0.14 16.62 9 2 1.47 77.58 -0.15 15.60 10 last 1.44 -9.92 0 0

The characteristics of the patch array antenna 700 and the comb line array antenna 710 according to an embodiment of the present invention are described in FIGS. 8A to 8C.

Figures 8A to 8C are diagrams explaining the characteristics of a patch array antenna and a comb line array antenna according to an embodiment of the present invention.

Graph 800 in FIG. 8A illustrates the relative amplitude and combining efficiency for a sidelobe level (SLL) of -20 dB for a patch array antenna and a combline array antenna.

In the graph 800, the graph line 801 may represent a patch array antenna, and the graph line 802 may represent a comb line array antenna.

The horizontal axis of the graph 800 represents the number of antenna elements, the left vertical axis represents relative amplitude, and the dominant axis represents coupling efficiency.

Referring to the graph 800 in FIG. 8A, the serially supplied patch and combline array antennas from the first antenna element to the ninth antenna element must have coupling efficiencies in the range of 0.8% to 59.2% and 2.3% to 79.8%, respectively. can confirm.

According to graph 800, the amplitude distribution of patch and combline array antennas is not symmetrical compared to the amplitude distribution of the Dolph-Chebyshev array factor.

This may be because the antenna element is not an ideal point source in a traveling wave serial feed array antenna, which is not the case in the Dolphchebyshev array coefficient calculation, and in traveling wave mode it is desirable for the last antenna element to radiate all remaining power.

Graph 810 in FIG. 8B illustrates the reflection coefficient of the last antenna element of a patch array antenna and a combline array antenna.

Referring to the graph 810 in FIG. 8B, the horizontal axis represents the frequency, the vertical axis represents the reflection coefficient, the graph line 811 represents the last antenna element of the patch array antenna, and the graph line 812 represents the It can represent the last antenna element of a comb line array antenna.

With respect to the last antenna element of the patch array antenna and the combline array antenna, L _s10 may be 0.4 mm, W _s10 may be 0.24 mm, L may be 1.31 mm, and W may be 1.32 mm.

The last antenna element of the patch array antenna and combline array antenna is oriented in each polarization direction and coincides with the input port, so that residual power can be efficiently dissipated.

The simulation results in graph 810 show that the reflection coefficients of the series-fed patch and the last element of the combline array are -22 dB and -25 dB, respectively, at 76.5 GHz.

For example, the phase of the radiated electric field at the last antenna of a patch array antenna and a combline array antenna may be 97º and -10º, respectively.

Graph 820 in FIG. 8C shows the distance between antenna elements for in phase excitation in a patch array antenna and a combline array antenna.

The distance according to the graph 820 may be a distance calculated based on Equation 1.

The parameters of each antenna element for in-phase excitation can be summarized through Tables 1 and 2 above.

The length of the input transmission line (L _in ) can be determined to make the transmission coefficient phase (∠S ₂₁ ) approximately “0”.

Therefore, the transmission coefficient phase (∠S ₂₁ ) can be neglected in determining the distance for in-phase excitation.

However, when connecting antenna elements, an unwanted phase offset occurs due to mutual coupling of the two antenna elements, so the transmission coefficient phase (∠S _21,1~n+1 ) from the first antenna element to the N+1 antenna element is used. This allows the offset to be identified.

For example, when the type of antenna element changes, the distance between the antenna elements changes, and it can be confirmed that the shortest distance in the seventh distance (d ₇ ) in the patch array antenna corresponds to the switch from the second type to the third type. there is.

The reason is that the eighth antenna element using a coupling structure at the output port of the transmission line has a low radiation field phase (∠E _r ).

The sharp increase in the eighth distance (d ₈ ) is due to the similar phase of the radiation field (∠E _r ) between the eighth and ninth antenna elements.

Similarly, the reduction of the fourth distance (d ₄ ) in a combline array antenna is mainly due to a significant drop in the phase (∠E _r ) of the radiated field from the first type to the second type.

9A and 9B are diagrams illustrating simulation results of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Figure 9a illustrates a simulated radiation pattern of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Referring to graph 900 in FIG. 9A, it illustrates co-polarized radiation patterns simulated using existing methods and the present invention at design frequencies.

The horizontal axis of the graph 900 represents the angle, the vertical axis represents the normalized gain, the graph line 901 represents a patch array antenna according to the prior art, and the graph line 902 represents the patch according to the present invention. It represents an array antenna, and the graph line 903 represents a comb line array antenna according to the prior art, and the graph line 904 represents a comb line array antenna according to the present invention.

Looking at graph lines 901 and 903, the prior art failed to compensate for the mutual coupling effect, and as a result, the series-fed patch and combline line arrays had main beam directions of -4º and -3º, respectively.

In addition, it can be seen that there are SLLs of -18.3dB and -18.5dB, respectively, and that the uncompensated phase delay in both the patch array antenna and the combline antenna according to the prior art tilts the main lobe and increases the SLL.

Meanwhile, the present invention considers ∠S _21,1~n+1 to eliminate the phase delay due to the mutual coupling effect, so Equation 1, the proposed equation without an iterative process to find the optimal distance in the array, The main beam directions of the patch array antenna and combline array antenna were set to 0º and SLL -21.7 dB and -20.1 dB, respectively.

Therefore, these results demonstrate that Equation 1, the proposed equation for the optimal distance between antenna elements, can successfully compensate for the phase delay of the microstrip traveling wave serial feed array antenna.

Figure 9b illustrates the reflection coefficient of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Referring to the graph 910 in FIG. 9B, the horizontal axis represents the frequency, the vertical axis represents the reflection coefficient, the graph line 911 represents the measured value of the patch array antenna, and the graph line 912 represents the measurement value of the comb line array antenna. It represents the measured value, and the graph line 913 represents the simulation value of the patch array antenna, and the graph line 914 represents the simulation value of the comb line array antenna.

The reflection coefficient was measured using a vector network analyzer, Agilent E8364B, and the measured reflection coefficients of the series-fed patch and combline array antenna are -21.8 dB and -15.4 dB at the design frequency of 76.5 GHz.

The measured results show minimal reflection at lower frequencies with a slight degradation compared to the simulated results, and the main causes of the resonance shift are expected to come from manufacturing errors in the substrate's dielectric constant offset and back-shorts. It is expected.

Figure 10 is a diagram illustrating a design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Figure 10 illustrates a design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention.

Referring to FIG. 10, in step 1001, the design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention includes the transmission coefficient phase of the first antenna element to the transmission coefficient phase of the N+1th antenna element. Taking this into account, the distance between the Nth antenna element and the N+1th antenna element can be determined.

In other words, the design method of the microstrip traveling wave serial feed array antenna is the length of the output transmission line of the Nth antenna element (L _out,n ), and the length of the input transmission line of the N+1th antenna element (L _in,n+1 ). , the induced wavelength of the transmission lines (λ _g ), the phase of the radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), and the phase of the radiation field in the reference direction of the N antenna element (∠E _{r, n} ), the Nth antenna element and the N+1th antenna element using the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1th antenna element. The distance (d _n ) between antenna elements can be determined.

Meanwhile, the design method of the microstrip traveling wave serial feed array antenna can determine the distance (d _n ) between the Nth antenna element and the N+1th antenna element using Equation 1 described above.

In step 1002, the design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention can determine the coupling efficiency by considering the power loss between the Nth antenna element and the N+1th antenna element according to the distance. .

In other words, the design method of the microstrip traveling wave serial feed array antenna is combined by considering the power loss (P _loss,n ) between the Nth antenna element and the N+1th antenna element based on the distance (d _n ) determined in step 1001. Efficiency can be determined.

For example, in the case of a patch array antenna, the distance (d _n ) is related to the transmission coefficient phase and the phase of the radiation field in the reference direction, and the phase is related to the width (W) and length (L) of the transmission lines. ), or adjust the width (W) of the square-shaped cut applied to the width (W) and length (L) of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element. _s ) and length (L _s ), or by adjusting the distance between the centers of any one of the transmission lines and the first antenna element, the Nth antenna element, and the N+1th antenna element. there is.

In addition, in the case of a comb line array antenna, the distance (d _n ) adjusts the size of the inserted slit with respect to the width (W) and length (L) of the transmission lines, or the size of the inserted slit or the first antenna element and the Nth antenna element. And adjusting the width (W _e ) of each of the N+1 antenna elements, or adding stubs to each of the first antenna element, the N antenna element, and the N+1 antenna element, and the length of the added stub (L _s ). And it can be adjusted by adjusting the width (W _s ), the distance between the added stubs (g), and the distance connected at the end (D).

In step 1003, the design method of a microstrip traveling wave serial feed array antenna according to an embodiment of the present invention can arrange antenna elements based on coupling efficiency.

That is, the design method of the microstrip traveling wave serial feed array antenna may arrange the first antenna element, the Nth antenna element, and the N+1th antenna element based on the coupling efficiency determined in step 1002.

For example, the design method of a microstrip traveling wave serial feed array antenna is to arrange the fourth antenna element based on the optimal distance between the third and fourth antenna elements when N is 3, and when N is 4 Antenna elements can be arranged sequentially.

Therefore, the present invention can provide a design method for a microstrip traveling wave serial feed array antenna that determines the optimal distance to the in-phase radiation field in the reference direction without an iterative optimization process in the design of the microstrip traveling wave serial feed array antenna.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the scope of the patent application is not limited or limited by these examples. The same reference numerals in each drawing indicate the same members.

Although the embodiments have been described with limited drawings as described above, various modifications and variations can be made by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims (13)

In the microstrip traveling wave serial feed array antenna design method including a first antenna element, an N-th antenna element, and an N+1-th antenna element interconnected by transmission lines,
Considering the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element, the Nth antenna element and the N+ 1 determining the distance (d _n ) between antenna elements;
determining coupling efficiency by considering power loss (P _loss,n ) between the N-th antenna element and the N+1-th antenna element according to the determined distance (d _n ); and
And arranging the first antenna element, the Nth antenna element, and the N+1th antenna element based on the determined coupling efficiency.
Microstrip traveling wave serial feed array antenna design method. According to paragraph 1,
Considering the transmission coefficient phase (∠S _21,1 ) of the first antenna element to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element, the Nth antenna element and the N+ 1 The step of determining the distance (d _n ) between antenna elements is:
Length of the output transmission line of the Nth antenna element (L _out,n ), length of the input transmission line of the N+1th antenna element (L _in,n+1 ), and guided wavelength of the transmission lines (λ _g ) , the phase of the radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), the phase of the radiation field in the reference direction of the Nth antenna element (∠E _r,n ), the first antenna element Characterized by determining the distance (d _n ) using the transmission coefficient phase (∠S _21,1 ) to the transmission coefficient phase (∠S _21,n+1 ) of the N+1 antenna element. to do
Microstrip traveling wave serial feed array antenna design method. According to paragraph 1,
Adjusting the size of the inserted slit with respect to the width (W) and length (L) of the transmission lines;
Width (W s ) and length of a square-shaped cut applied to the width (W ₎ and length (L) of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element adjusting (L _s ); and
Further comprising the step of adjusting the distance between any one of the transmission lines and the centers of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element.
Microstrip traveling wave serial feed array antenna design method. According to paragraph 3,
The step of adjusting the size of the inserted slit with respect to the width (W) and length (L) of the transmission lines is,
A step of reducing reflection at the input port of the transmission line by adjusting the length (L _slit ), width (W _slit ), and distance from the edge of the antenna element to the slit (D _slit ) of the slit according to the size of the adjusted slit. Characterized by including
Microstrip traveling wave serial feed array antenna design method. According to paragraph 3,
Adjusting the width (W s ) and length (L _s ) of the square cut applied to the width (W) and length (L) of each of the first antenna element, the N-th antenna element, and the N _+1-th antenna element. The steps are:
In order to adjust the return loss according to the width (W) of each of the first antenna element, the Nth antenna element, and the N+1th antenna element on the input side of the transmission lines, the width (W _s ) and the length (L _s ), characterized in that it includes the step of adjusting
Microstrip traveling wave serial feed array antenna design method. According to paragraph 3,
The step of adjusting the distance between any one of the transmission lines and the centers of each of the first antenna element, the Nth antenna element, and the N+1th antenna element includes,
Characterized in that it comprises the step of adjusting the coupling induction for radiated power based on the adjusted spacing, and adjusting the coupling efficiency based on the adjusted coupling induction.
Microstrip traveling wave serial feed array antenna design method. According to paragraph 1,
Adjusting the size of the inserted slit with respect to the width (W) and length (L) of the transmission lines;
adjusting the width (W _e ) of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element; and
A stub is added to each of the first antenna element, the Nth antenna element, and the N+1th antenna element, and the length (L _s ) and width (W _s ) of the added stub, and the distance between the added stub and the added stub, Characterized in that it further comprises the step of adjusting the gap (g) and the distance connected from the end (D)
Microstrip traveling wave serial feed array antenna design method. In clause 7,
The step of adjusting the width (W _e ) of each of the first antenna element, the N-th antenna element, and the N+1-th antenna element is,
By adjusting the signal and radiation path according to the adjusted width (W _e ), the length of the input transmission line (L _in ) and the phase of the radiation field in the _reference direction (∠ E _r ) is adjusted to control the binding efficiency.
Microstrip traveling wave serial feed array antenna design method. In clause 7,
A stub is added to each of the first antenna element, the Nth antenna element, and the N+1th antenna element, and the length (L _s ) and width (W _s ) of the added stub, and the distance between the added stub and the added stub, The step of adjusting the gap (g) and the distance connected from the end (D) is,
Characterized by controlling the coupling efficiency by adjusting the size of the width (W _s ) and the phase (∠E _r ) of the radiation field in the reference direction.
Microstrip traveling wave serial feed array antenna design method. According to paragraph 1,
The first antenna element, the Nth antenna element, and the N+1th antenna element are any one of a patch serial feed array antenna element and a comb line serial feed array antenna element.
Microstrip traveling wave serial feed array antenna design method. It includes a first antenna element, an N-th antenna element, and an N+1-th antenna element that are interconnected by transmission lines,
The Nth antenna element and the N+1th antenna element have a transmission coefficient phase of the first antenna element (∠S _21,1 ) to a transmission coefficient phase of the N+1th antenna element (∠S _21,n+1 ) is determined based on the distance (d _n ) between the N-th antenna element and the N+1-th antenna element, and between the N-th antenna element and the N+1-th antenna element according to the determined distance (d _n ) The coupling efficiency is determined considering the power loss (P _loss,n ), and is arranged together with the first antenna element based on the determined coupling efficiency.
Microstrip traveling wave serial feed array antenna. According to clause 11,
The distance (d _n ) between the Nth antenna element and the N+1th antenna element is the length of the output transmission line of the Nth antenna element (L _out,n ), and the length of the input transmission line of the N+1th antenna element. Length (L _in,n+1 ), guided wavelength of the transmission lines (λ _g ), phase of the radiation field in the reference direction of the N+1 antenna element (∠E _r,n+1 ), and the N antenna element Phase of the radiation field in the reference direction (∠E _r,n ), transmission coefficient phase of the first antenna element (∠S _21,1 ) to transmission coefficient phase of the N+1 antenna element (∠S _{21,n+ 1} ), characterized in that it is determined using
Microstrip traveling wave serial feed array antenna. According to clause 11,
The first antenna element, the Nth antenna element, and the N+1th antenna element are any one of a patch serial feed array antenna element and a comb line serial feed array antenna element.
Microstrip traveling wave serial feed array antenna.