Dual-square loop element antenna configured with a reflector using a circular loop element and a gate element

Abstract

An antenna that can be placed near a window with a depth of about 100 mm and can receive broadcasts from local TV stations is composed of a combination of well-known antenna element shapes. 【Solution means】The antenna combines a double-square loop element, a circular loop element, and a gate element, which are well-known antenna element shapes, as follows. Let λ be the wavelength of the target frequency. First, a vertical rectangle with a short side of about 0.22λ and a long side of about 0.5λ is provided with a feeding segment to form a double-square loop feeding element. For the upper segment of the double-square loop element, a gate element with a side length of about 0.167λ is placed at a distance of about 0.117λ behind the direction of radio wave arrival, such that its upper side is approximately at the same height as the upper segment of the double-square loop element. A circular loop element is placed as a reflector at a distance of about 0.117λ behind the direction of radio wave arrival, such that the center of the lower square of the double-square loop element and the center of the circular loop element are at approximately the same height.

Description

Technical Field

[0001] The present invention relates to an antenna device.

Background Art

[0002] As indoor antennas for receiving terrestrial digital television broadcasts, a dipole antenna and a loop antenna can be considered (Patent Document 1). However, with a dipole antenna or a loop antenna, the gain may be insufficient and it may not be possible to receive a specific broadcasting station. There is also an example of using three rod-shaped elements as reflectors for a double-square loop element antenna (Non-Patent Document 1), but the dimensions become large, and three or more attachment points for the reflector must be provided, and it lacks design appeal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An antenna that can be placed near a window with a depth of about 100 mm and receive broadcasts from local TV stations is configured by a combination of well-known antenna element shapes.

Means for Solving the Problems

[0006] A double-square loop element, a circular loop element, and a gate-shaped element, which are well-known antenna element shapes, are combined as follows. Taking λ as the wavelength of the target frequency, first, a vertical rectangle with a short side of about 0.22λ and a long side of about 0.5λ is provided with a feeding segment that divides it vertically at the center of the long side to form a double-square loop feeding element. For the upper segment of the double-square loop element, a gate-shaped element with each side length of about 0.167λ is placed at a distance of about 0.117λ behind the direction of radio wave arrival, such that its upper side is approximately at the same height as the upper segment of the double-square loop element. A circular loop element is placed at a distance of about 0.117λ behind the direction of radio wave arrival, such that the center of the lower square of the double-square loop element and the center of the circular loop element are at approximately the same height. Note that the gate-shaped element is originally a dipole-type element that has been roughly divided into three parts and has both sides bent downward to reduce the width. Note that the gate-shaped element and the circular loop element are not fed.

Advantages of the Invention

[0007] When the target frequency is 500 MHz, the height of the antenna of the present invention is about 350 mm, the width is about 202 mm, and the depth is about 70 mm, which is a size that can be placed near the window even with a suitable mount. When simulated with antenna simulation software, it has a gain of about 7 dBd (about 9.15 dBi) while having the above dimensions. When simulating the impedance of the present antenna configuration, in the configuration of

[0006] , at 500 MHz, it has a pure resistance component of about 75 Ω and a reactance component of about 0 Ω. Thus, it can be connected to a 75 Ω coaxial cable without inserting a matching circuit. Also, regarding the pure resistance component and reactance component of the present invention, the impedance can be easily adjusted by changing the length of the gate-shaped element, the diameter of the circular loop element, and the distance from the double-square loop element to the reflector composed of the gate-shaped element and the circular loop element.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0009] Adhere a wooden vertical support plate to a wooden horizontal support base. Use a fixing band to attach a double-square loop element to the vertical support plate. The double-square loop element is formed by soldering a copper wire or copper tube with a diameter of 3 mm. Connect a coaxial cable to the power supply part of the double-square loop element. A circular loop element is formed by soldering using a copper wire or copper tube with a diameter of 3 mm. Similarly, a portal element is formed using a copper wire or copper tube with a diameter of 3 mm. The circular loop element and the portal element constitute a reflector, which is attached to the back of the vertical support plate.

Example

[0010] Figure 1 is a perspective view showing the antenna of an embodiment of the present invention.

[0011] As shown in Figure 1, the antenna of this embodiment is composed of a double-square loop element 1, a horizontal support base 2, a vertical support plate 3, a circular loop element 4, a portal element 5, and a coaxial cable 6. Attach the upper segment 7 and the lower segment 8 of the double-square loop element 1 to the vertical support plate 3 with a fixing band 9, and attach a reflector composed of a circular loop element 4 and a portal element 5 to the rear part of the vertical support plate 3 with a fixing band. Provide a power supply part 11 at the center of the middle segment 10 of the double-square loop element 1 and connect it to the coaxial cable 6 by soldering.

[0012] Figure 2 is a view of only the antenna element of the present invention as seen from the back. In this example, in order to improve the mountability of the reflector, the circular loop element 4 and the portal element 5 are connected by a vertical segment 12.

Explanation of Reference Numerals

[0013] 1 Double-square loop element 2 Horizontal base 3 Vertical plate 4 Circular loop element 5 Portal element 6 Coaxial cable 7 Upper segment 8 Lower segment 9 Fixed band 10 Middle segment 11 Power supply section 12 Vertical segment of the reflector

Claims

[Claim 1] This antenna shape has a feed point on the middle segment of the biquadratic loop element, and when the direction of radio wave arrival is forward, it has a reflector consisting of a circular loop element and an element shaped like the katakana character "C" rotated 90 degrees to the left (hereinafter referred to as a "gate-shaped element") behind the biquadratic loop element.

Images