JP4883573B2 - Antenna and oscillator using it - Google Patents

Description

  The present invention relates to an antenna and an oscillator using the antenna, and more particularly to an oscillator using an electrode of an active element manufactured on a substrate as an antenna or a resonant circuit / antenna.

  Electromagnetic waves in a band extending from millimeter waves through submillimeter waves to far infrared rays are widely called terahertz electromagnetic waves or terahertz light. In many cases, the lower limit of the frequency is 100 to 300 GHz and the upper limit is 10 to 100 THz. In Non-Patent Documents 1 and 2, the domestic and foreign research and development trends in various semiconductor devices used for oscillation and amplification in the terahertz region of 100 GHz and above are based on various diode and transistor materials, operating principles, specific structures, characteristics, etc. Have been reported.

  Similarly, Non-Patent Documents 3 and 4 report manufacturing technologies of various semiconductor devices and mounting techniques of voltage controlled oscillators (VCOs) and MMICs (Monolytic Microwave Integrated Circuits), which are application examples using semiconductor devices as oscillators. ing.

  Non-Patent Document 5 reports that an oscillation of 0.6 THz or more was obtained by using a slot antenna as an external resonance circuit also serving as an antenna as an oscillator in which an antenna and a resonant tunnel diode are integrated on a substrate. In Non-Patent Document 5, in order to control the equivalent circuit characteristics of the semiconductor element electrode / antenna portion corresponding to the resonance circuit portion, a slot antenna is realized between a pair of electrodes, and a metal is used to determine its length. -An MIM reflector having a three-layer structure of insulator-metal (MIM) is introduced. This complicates the structure of the oscillation device and increases the number of semiconductor manufacturing processes.

  Non-Patent Document 6 reports a design using a negative resistance dual channel transistor (NDR-DCT), but the possibility of oscillation with a large margin that has been confirmed has remained above about 1 THz. Yes.

  According to Non-Patent Document 7, an oscillation circuit using a diode, a transistor or the like is generally described as an analysis of an equivalent circuit in which these elements are connected to an external resonance circuit in parallel as a circuit including a negative resistance.

  As shown in FIG. 28, the slot antenna 60 forms a long slit 62 (also referred to as a slot) on a conductor plate 61, and when a high frequency voltage 63 is fed to the slot 62, an electric field is generated in a direction across the cut. This is one of the basic antennas that serve as a wave source and radiate an electromagnetic field around the conductor plate 61. The slot antenna 60 is known as a complementary antenna of a dipole antenna, and its operating principle is well elucidated. Non-Patent Document 8 describes that a slot antenna can be handled in the same manner as a linear conductor having the same length, that is, a dipole antenna. It is described that these antennas resonate when their length is an integral multiple of the half-wavelength of the high frequency to be fed, particularly 1 times, and the radiation ability of radio waves is increased.

Eiichi Sano, “Prospects for Device Technology Aiming for Terahertz Oscillation”, IEICE Transactions C Vol.J87-C No.5 pp.413-423, May 2004 Takakazu Kashiwagi, "Possibility of ultra-high-speed compound semiconductor electronic devices", IEICE Transactions C Vol.J89-C No.3, pp.79-86, 2006 Aikawa et al., “Monolithic Microwave Integrated Circuit (MMIC)”, The Institute of Electronics, Information and Communication Engineers, pp. 19-65, January 1997 Supervised and edited by the “Millimeter-wave technology basics and applications” Editorial Committee, “Millimeter-wave technology basics and applications” Realize, pp. 46-73, pp. 99-133, July 31, 1998 Naoyuki Orihashi, et al., “Experimental and Theoretical Characteristics of Sub-Terahertz and Terahertz Oscillations of Resonant Tunneling Diodes Integrated with Slot Antennas”, Japanese Journal of Applied Physics, Vol.44, No.11, pp.7809-7815, 2005 Furuya et al., “Analysis of Terahertz Transmitter Using Negative Resistance Dual Channel Transistor”, Proceedings of Proceedings of 2006 Society Conference of IEICE, Proceedings of 2006 IEICE Electronics Society Conference, C-10-8 Pp. 49, September 7, 2006 Suzuki Masaomi, “[Sadamoto] Designing a Transistor Circuit”, pp. 314-318, CQ Publishing Co., Ltd., July 1, 2004, 14th edition Yasuto Mushiaki, “Easy Talk of Radio Waves and Antennas-Discovery of the Principle of Ultra Broadband”, pp. 46-52, pp. 66-69, Ohm Corporation, August 25, 2001

  As an example in which an antenna or a resonance circuit needs to be configured by using two conductors that are not allowed to be short-circuited in direct current, semiconductor substrates such as transistors and diodes as described in Non-Patent Documents 5 and 6 above are used. In some cases, an oscillator integrated in the above is realized. In this case, the above-described oscillation condition must be satisfied at a desired frequency by adjusting the characteristic of the external resonance circuit connected to the predetermined equivalent circuit characteristic of the negative resistance circuit portion (FIG. 12). reference). For this purpose, it is desirable that the characteristics of the resonance circuit greatly change with respect to the frequency and that the change can occur at a desired frequency. That is, the realization of a sharp resonance and the accompanying strong electromagnetic field radiation and the control of the resonance frequency are generally performed in an antenna. A half-wave dipole antenna, which is one of the basic and representative antennas, consists of two linear conductors, has a relatively sharp resonance, and the resonance frequency can be changed by changing the antenna length. Can be a candidate for an external resonant circuit that satisfies various requirements. The same applies to a slot antenna which is a complementary antenna of a dipole antenna.

  However, the dipole antenna has a problem that a sharp resonance cannot be obtained when a conductor constituting the dipole antenna is not linear and has a certain extent such as a flat plate.

  In particular, it becomes an obstacle when the above-described resonance circuit is configured by using an electrode formed on a substrate like a semiconductor element such as a diode or a transistor. This electrode has a problem that it is generally difficult to make it linear, for example, because it cannot be made smaller than the channel width of a transistor or a certain size is required for wire bonding. is there.

  The length of the slot antenna also determines the resonance wavelength and must be finite. Since each electrode of the diode is connected to the anode and cathode, and each electrode of the transistor is connected to the source, drain, gate, etc., it is natural that mutual short circuit is not allowed. It is not possible to close both ends of the gap to make both ends of the slot antenna.

When a three-terminal element is used as a semiconductor element, a slot antenna must be formed by two electrodes connected to these terminals, and a region for wiring the remaining one electrode must be secured.

  In view of the above problems, a first object of the present invention is to provide a novel antenna that has good resonance characteristics at a desired frequency. The second object of the present invention is to provide an oscillator using this antenna.

In order to achieve the first object, the slot antenna of the present invention has two conductive flat plates arranged so as to form a slit at a predetermined interval, and the two conductive flat plates include Further, two sets of slit reflector portions each having a gap formed in a direction perpendicular to the longitudinal direction of the slits are provided, and the slits sandwiched between the two sets of slit reflector portions serve as a slot antenna body.
According to the above configuration, the slot portion sandwiched by two sets of slit reflector portions on two separated conductor flat plates constituting the slit becomes the slot antenna body, and the electromagnetic field can be localized and resonated. The frequency dependence of the impedance characteristics of the slot antenna can be controlled by changing the width and length of the two sets of slit reflector portions and the distance between them.

  In the above configuration, a slit reflector portion may be further disposed on the conductive flat plate. If the slit reflectors are further provided in the two sets of slit reflectors, not only the termination can be realized, but also the degree of resonance can be finely adjusted. The resonance characteristics of the slot antenna can be controlled more finely.

  In the above configuration, preferably, a slit reflector portion is further disposed in the vicinity of the feeding point of the slot antenna body. In this case, the slit reflector portion arranged at the feeding point of the slot antenna body operates as a so-called stub, and the matching characteristics between the AC power source connected to the feeding point and the slot antenna can be improved. Therefore, the power from the AC power source can be efficiently supplied to the slot antenna by adjusting the length and width of the slit reflector portion provided in the vicinity of the feeding point.

  A plurality of slot antennas according to any one of the above descriptions may be arranged to constitute an array antenna. It is possible to control the radiation directivity and improve the gain by adjusting the distance and relative arrangement between the antenna elements arranged in large numbers. Similarly, the antenna elements are generally coupled to each other, and their equivalent circuit characteristics change differently from the case where each antenna element exists as a single element. This can be used to adjust the resonance and the degree thereof as described above.

In order to achieve the second object, an oscillator of the present invention is an oscillator comprising an active element and a slot antenna, wherein at least two electrodes of the active element are conductive plates, and two conductive plates are predetermined. The two conductive flat plates are arranged so as to form a slit at an interval of at least two gaps to be slit reflector portions in the direction perpendicular to the longitudinal direction of the slit, and two sets The slit sandwiched between the slit reflector portions described above is a slot antenna main body, and the slot antenna serves as both a resonator and an antenna.

  In the above configuration, a slit reflector portion may be further disposed on the two conductive flat plates. A slit reflector portion may be disposed in the vicinity of the feeding point of the slot antenna body. The active element and the slot antenna are preferably integrated on a substrate. The active element is preferably a transistor or a negative resistance diode.

  According to the above configuration, an array type oscillator is configured by arranging a large number of active elements and slot antennas on the substrate. Thereby, the output of the oscillator can be increased.

  According to the slot antenna of the present invention, a slot antenna is provided that can adjust the degree of resonance sharpness and the frequency at which the resonance occurs by providing a slit reflector in the slot antenna body, that is, can control characteristics such as input impedance. can do.

  According to the oscillator using the slot antenna of the present invention, it is possible to provide an oscillator in which an active element of a transistor and a diode manufactured on a substrate and a slot antenna are integrated.

Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings. In each figure, the same or corresponding members are denoted by the same reference numerals.
An antenna according to a first embodiment of the present invention will be described.
1A and 1B are diagrams schematically showing a configuration of a slot antenna according to the present invention, FIG. 1A is a perspective view showing the configuration, and FIG. 1B is a diagram showing an AC power supply to a power feeding portion of the slot antenna of FIG. It is a top view which shows a mode that it connected.
As shown in FIG. 1 (A), the slot antenna 1 of the present invention includes a gap having a length L ₀ and a width W ₀ as a slot antenna body 2 and a longitudinal direction of the gap 2 (Y direction in FIG. 1). ) And a slit reflector portion 3 formed of a gap having a length L ₁ and a width W _1. The slit reflector portion 3 is arranged in a direction perpendicular to (X direction in FIG. 1). In the illustrated case, the slit reflector portion 3 is formed of gaps 3A and 3B in the X direction so as to form a cross with respect to the slot antenna body 2. 'The length of and 3B L _1' length _{L 1} of the space 3A 'may be the same.

  The slot antenna 1 can be formed by providing gaps to be the slot antenna body 2 and the slit reflector portion 3 in the conductive flat plate 5 having good conductivity. In the case of illustration, the space | gap 3 used as a slit reflector part is provided in the left side and the right side of the electroconductive flat plate 5 in which the slot antenna 1 is formed.

  The conductive flat plate 5 may be formed on the substrate 6 as shown. As such a substrate 6, a material such as an insulator or a semiconductor can be used. The thickness of the conductive flat plate 5 may be a thickness that does not cause a loss at the frequency to be used, and may be a thickness greater than the skin depth determined by the conductivity of the conductive flat plate 5 and the use frequency.

  As shown in FIG. 1 (B), the feeding portion 2A in the slot antenna body 2 of the slot antenna 1 according to the present invention is provided in the central portion of the slot antenna body 2. The slot antenna 1 is excited by connecting an AC power source 7 to the power feeding unit 2A.

According to the slot antenna 1 of the present invention, the frequency characteristic of the impedance or admittance of the two-terminal pair at the feeding point is determined by the location where the slit reflector unit 3 is disposed in the slot antenna body, its length L ₁ and width W ₁ . It can be adjusted by changing. Therefore, according to the slot antenna 1 of the present invention, the resonance characteristic can be controlled by changing the frequency characteristic of the impedance.

A slot antenna according to a second embodiment of the present invention will be described.
FIG. 2 is a perspective view schematically showing the configuration of the slot antenna 10 according to the second embodiment of the present invention.
As shown in FIG. 2, the slot antenna 10 according to the second embodiment of the present invention has two conductive flat plates 11 and 12 arranged so as to form a gap having a width of W ₀ . A first composed of a gap (also referred to as a slit) having a length L ₁ and a width W ₁ arranged in a direction (X direction in FIG. 2) perpendicular to the longitudinal direction (Y direction in FIG. 2) of the gap. a slit reflector portion 3, a length which is formed of the same gap and this is a second slit reflector portion 13 width L ₂ consists gap W _2, and a.

Here, since the 1st and 2nd slit reflector parts 3 and 13 are formed by forming a space | gap in each of the electroconductive flat plates 11 and 12, they are called 2 sets of slit reflector parts. The gap sandwiched between the two slit reflector parts 3 and 13 is a gap having a width W ₀ and a length L ₀ , and becomes the slot antenna body 2, and the feeding point thereof is the central portion of the slot antenna body 2. It has become. The slit reflector 3 is arranged in the direction perpendicular to the longitudinal direction of the slot antenna body 2, but the width and length of the gap may be the same size.

In the slot antenna 10 according to the second embodiment of the present invention, the gap having a width of W ₀ separating the two conductor plates 11 and 12 arranged in close proximity is a kind of slot waveguide (also called a slot line). This can be regarded as non-patent document 3). Here, if the first and second slit reflector portions 3 and 13 are provided in a part of the slot waveguide as described above, the impedance is different from the original impedance of the slot waveguide and mismatch occurs. When the degree of mismatch is sufficiently large, the electromagnetic field propagating through the slot waveguide, that is, the slot antenna body is reflected by the mismatched portion, and most of the energy does not propagate further. This is because the first and second slit reflector portions 3 and 13 act as terminations provided in the slot antenna body. The slot antenna 10 can be considered as a finite-length slot waveguide terminated by the first and second slit reflector portions 3 and 13.

According to the slot antenna 10 of the present invention, the resonance frequency is inversely proportional to the ideal length L ₀ of the first and second opposite ends separated by a slot antenna body part slit reflector portion 3 and 13 described above, Further, the state of resonance, that is, the frequency characteristic of the impedance or admittance of the two-terminal pair at the feeding point can be adjusted by changing the length and width W of the first and second slit reflector portions 3 and 13. it can. Therefore, according to the slot antenna 10 of the present invention, the resonance characteristic can be controlled by changing the frequency characteristic of the impedance.

  The degree of misalignment realized by the slit reflectors 3 and 13 differs depending on dimensions such as the width, length, and thickness of the conductive flat plate. It is also possible to add control that is not a realization of simple reflection. In this case, the slit reflectors 3 and 13 may be considered to be not necessarily perfect reflectors, that is, reflectors.

Next, a first modification of the antenna according to the second embodiment of the present invention will be described.
FIG. 3 is a perspective view schematically showing a configuration of a first modification of the slot antenna according to the second exemplary embodiment of the present invention. As shown in FIG. 3, in the first modification of the slot antenna according to the second embodiment, the slot antenna 15 further includes two sets of slit reflector portions 14 and 14 as compared with the slot antenna 10 shown in FIG. 2. Is different.

  According to the slot antenna 20, since the resonance frequency characteristics are further provided with the two slit reflector sections 14 and 14 in the first and second slit reflector sections 3 and 13, the resonance characteristics can be controlled more finely. Can do.

A second modification of the antenna according to the second embodiment of the present invention will be described.
FIG. 4 is a perspective view schematically showing a configuration of a second example of the slot antenna according to the second embodiment of the present invention. As shown in FIG. 4, in the second modified example of the slot antenna according to the second embodiment, the slot antenna 20 is adjacent to the first slit reflector unit 3 as compared with the slot antenna 10 shown in FIG. The difference is that the slit reflector portion 16 is provided. Two sets of the slit reflector portions 16 may be provided.

  According to the slot antenna 20, since the slit reflector 16 is further provided adjacent to the first and second slit reflectors 3 and 13, the resonance frequency characteristic can be controlled more finely.

A third modification of the antenna according to the second embodiment of the present invention will be described.
FIG. 5 is a perspective view schematically showing a configuration of a third modification of the slot antenna according to the present invention. As shown in FIG. 5, the third modification 25 of the slot antenna according to the present invention is different from the slot antenna 20 shown in FIG. 4 in that a slit reflector 18 is further provided in the vicinity of the feeding point 2A. is there. In the illustrated case, the slit reflector 18 is provided on one side of the feeding point 2A. Further, one or more slit reflector portions 18 may be provided on both sides of the feeding point.

  According to the slot antenna 25, the slit reflector portion 18 disposed at the feeding point operates as a so-called stub, and the matching characteristics between the AC power source connected to the feeding point and the slot antenna 25 can be improved. Therefore, by adjusting the length and width of the slit reflector portion 18 provided in the vicinity of the feeding point, the power from the AC power source can be efficiently supplied to the slot antenna. Slot antennas 10, 15, and 20 can also be applied to the slit reflector portion 18 provided in the vicinity of the feeding point.

Next, an array antenna using the slot antenna according to the third embodiment of the present invention will be described.
A large number of slot antennas 10, 15, 20, and 25 having the above-described configuration can be arranged side by side to form an array antenna. FIG. 6 is a perspective view schematically showing a configuration example of an array antenna using the slot antenna according to the third embodiment of the present invention. As shown in FIG. 6, the array antenna 30 is configured by arranging a large number of slot antennas 15 in a line at intervals d. The array antenna 30 may be a planar two-dimensional array or a three-dimensional array in addition to a linear shape.

  According to the array antenna 30, the radiation directivity can be controlled and the gain can be improved by adjusting the distance d between the slot antennas 15 and the relative arrangement thereof. The slot antennas 15 are coupled to each other, and their impedance characteristics change differently from the case where each slot antenna 15 exists in a single unit. Therefore, the slot antennas 15 are used for adjusting the resonance characteristics of the antennas constituting the array antenna. can do.

Next, an oscillator using the slot antenna of the present invention according to the fourth embodiment of the present invention will be described.
7 to 10 are perspective views schematically showing an oscillator using the slot antenna according to the present invention.
As shown in FIG. 7, the oscillator 35 using the slot antenna 10 of the present invention is composed of the slot antenna 10 and the active element 33 shown in FIG. The slot antenna 10 and the active element 33 are formed on a substrate 31, and a layer 32 including an active element is formed on the substrate 31, and an electrode of the active element formed on an insulating layer (not shown) is a slot. It also serves as the conductive flat plates 11 and 12 of the antenna. That is, the active element is connected to the power feeding portion of the slot antenna body shown in FIG. Since the configuration of the slot antenna 10 has already been described, a detailed description thereof will be omitted. When the active element is a diode, the anode electrode and the cathode electrode may serve as the conductive plates 11 and 12, respectively. When the active element is a transistor, the source electrode and the drain electrode may serve as the conductive plates 11 and 12, respectively. The gate electrode may be wired using a thin line in the gap of the slot antenna body 2.

  FIG. 8 shows an oscillator 40 using the slot antenna 15 according to the present invention. The difference from the oscillator 35 of FIG. 7 is that the slot antenna 15 further includes a slit reflector section 14.

  FIG. 9 shows an oscillator 45 using the slot antenna 20 according to the present invention. The difference from the oscillator 35 of FIG. 8 is that the slot antenna 20 further includes a slit reflector section 16.

FIG. 10 shows an oscillator 50 using a slot antenna according to the present invention. The difference from the oscillator 45 of FIG. 9 is that a slit reflector 18 is further provided in the vicinity of the feeding point 2A of the slot antenna 20. It is in. Here, the slit reflector 18 may be provided in the oscillators 35 and 40.

  As the two-terminal element, a so-called negative resistance diode can be used, and examples thereof include an Esaki diode (tunnel diode), a Gunn diode, an impat diode, a tannet diode, a barit diode, and a resonant tunnel diode.

  Examples of the three-terminal element transistor include various field effect transistors such as FET, MESFET, MOSFET, SIT, HEMT, and negative resistance dual channel transistor.

The operation of the oscillator of the present invention will be described.
FIG. 11 is a diagram showing an equivalent circuit of the oscillators 35, 40, 45, and 50 of the present invention. As shown in FIG. 11, the oscillator of the present invention has an admittance of an active element (hereinafter referred to as “Ya” as appropriate) and each of the admittances (hereinafter referred to as “Yd” without appropriate distinction) of the slot antennas 10, 15, and 20 of the present invention. Can be represented by a parallel circuit. In order for this oscillation circuit to oscillate, for the admittance Yd of the active element portion and the admittance Ya of the slot antenna, the following two oscillation conditions, that is, the gain condition and the phase condition must be satisfied simultaneously.
Gain condition:
Re (Yd) + Re (Ya) ≦ 0 (where Re (Yd) <0: negative resistance)
Phase condition:
Im (Yd) + Im (Ya) = 0
Here, Re and Im indicate the real part and the imaginary part of the admittance, respectively. Under the gain condition, it is better that Re (Yd) + Re (Ya) is smaller than zero.

FIG. 12 is a diagram schematically showing frequency characteristics of admittances of the active element and the slot antenna of the oscillator according to the present invention, where (A) does not satisfy the oscillation condition and (B) satisfies the oscillation condition. Is shown. In FIG. 12, the horizontal axis represents frequency and the vertical axis represents admittance.
As shown in FIG. 12B, the real part (conductance) of the admittance of the slot antenna becomes maximum at the resonance frequency, and its imaginary part (susceptance) becomes 0 at the resonance frequency fr. It turns into sex. On the other hand, the admittance of the active element is shown as a value obtained by inverting the sign, that is, multiplied by −1, and the frequency fo that satisfies the gain and phase conditions is the oscillation frequency of the active element. Therefore, the oscillator according to the present invention oscillates if the admittance characteristic of the active element is obtained and the admittance of the slot antenna is set so as to satisfy the above oscillation condition (see FIG. 12B).

  According to the oscillators 35, 40, and 45 of the present invention, the interval between the two sets of slit reflectors 3 and 13 can determine the resonance frequency, and the width and length of the two sets of slit reflectors 3 and 13 can be determined. By adjusting the resonator characteristics, the resonator characteristics can be appropriately designed. Furthermore, in the case of the oscillators 40 and 45, since the slit reflector portion 14 or 16 is further added, the resonator characteristics can be finely adjusted.

  According to each oscillator 50 of the present invention, since at least one set of slit reflector portions 18 can be added in the vicinity of the feeding point, the matching state between the active element 33 and the slot antenna portion is improved, and the output of the oscillator is improved. Can be made. Therefore, fine adjustment of the resonator characteristics becomes possible.

Next, a specific example of an oscillator using a slot antenna according to the fourth embodiment of the present invention will be described.
FIG. 13 is a perspective view schematically showing a specific example of an oscillator using a slot antenna according to the present invention. As shown in FIG. 13, the oscillator 35 using the slot antenna 10 of the present invention has the slot antenna 10 and the active element 33 shown in FIG. 2 formed on a semiconductor substrate. In the illustrated case, the drain electrode is a conductive flat plate 11 of a slot antenna, and the source electrode is a conductive flat plate 12 of a slot antenna. The gate electrode is formed above the drain electrode and the source electrode, and is connected to the gate of the active element 33 through a gate wiring provided at the center in the slit.

  FIG. 14 is a cross-sectional view of a structure including active elements along the line AA of the oscillator shown in FIG. As shown in FIG. 14, this active element is, for example, a negative resistance dual channel transistor, and is formed of an InAlAs buffer layer having a thickness of 10 nm and an InGaAs having a thickness of 10 nm on an InP (100) substrate. A mobility layer, a barrier layer made of InAlAs, a low mobility layer made of InGaAs, a spacer layer made of InAlAs, a δ-doping layer, a Schottky layer made of InAlAs with a thickness of 15 nm, a contact layer, Are sequentially stacked, and details thereof are described in Non-Patent Document 6. The negative resistance dual channel transistor can be manufactured, for example, by forming an active layer on an InP (100) substrate by molecular beam epitaxy (MBE) or the like, and forming source, drain, and gate electrodes. . In this case, each electrode can be formed by a CVD process for depositing an insulating film, a vapor deposition process for a metal material to be the electrode, or a lithography process or an etching process for patterning.

  As for an array antenna or an oscillator using an array antenna, a plurality of devices separated as described above can be prepared to have a desired arrangement. The arrangement method in this case can be any of linear, planar, and three-dimensional arrangement. Furthermore, you may use the several device produced simultaneously on the same board | substrate at the time of semiconductor element manufacture. Each antenna may share a part of the electrode of the semiconductor element. For example, a plurality of devices that are separated from each other may be configured to be short-circuited so as to share only the drain electrode.

  In the case of an active element, particularly a transistor, an inevitable electrode removal portion often occurs due to manufacturing restrictions. For example, if the source and drain electrodes have to be removed slightly on both sides of the channel in order to fabricate a gate electrode that crosses the channel of the transistor sandwiched between the source and drain electrodes, the gap is provided in the present invention. Can be diverted to a slit reflector used in the slot antenna. As a result, the oscillator according to the present invention can realize desired resonator characteristics of the slot antenna due to ease of manufacture, and can improve the degree of freedom in manufacturing the semiconductor.

The following is a design example of the oscillator of the present invention.
The NDR-DCT shown in Non-Patent Document 6 is used as a semiconductor element, a semiconductor element is manufactured, its characteristics are measured and analyzed, and a three-dimensional electromagnetic field analysis for designing an external resonator is performed by a finite element method. A numerical analysis tool (manufactured by Ansoft Japan Co., Ltd., HFSS) was used.

15A shows an equivalent circuit of the NDR-DCT, and FIG. 15B shows an equivalent circuit of the oscillator. As shown in FIG. 15A, in the equivalent circuit of the transistor, Rc is a contact resistance between the source or drain electrode and the semiconductor, Cc is a capacitance between the source or drain electrode and the semiconductor, and Rch is a channel resistance. -Gd and Cd are the differential negative conductance and the capacitance that are expressed by the transition between the dual channels immediately below the gate, respectively. Lg is the gate length.
The following values were used as equivalent circuit constants Rc, Cc, and Rch.
Rc = 1.39 × 10 ⁻³ Ω
Cc = 0.24pF
Rch = 12Ω

The equivalent circuit constants -Gd and Cd were determined for Lg = 100 nm and 200 nm, respectively, from the following mathematical formulas (1) and (2) with reference to Non-Patent Document 5.

Here, G (V _AC ) = a− (3b / 4) * V _AC ² , τ _Gate = Lg / v _s , and G (V _AC ) was obtained from the following formulas (3) and (4). . V ₀ corresponds to a DC bias.


Here, a = 3/2 * ΔI / ΔV, is b = ΔI / ΔV ^2. ΔI and ΔV were obtained from the measurement results of actual negative resistance of NDR-DCT. The carrier saturation speed v _s assumes that the carrier travels through the high mobility and low mobility channels under the gate in the same distance (Lg / 2) respectively, and the approximate saturation speed in each is 1.26 × 10 ^5. m / s. Τ _G
It was assumed that _ate >> _τtra . Here, τ _tra is the time required for transition between carriers (electrons) between dual channels.

  As shown in FIG. 15B, the equivalent circuit of the oscillator is represented by a parallel circuit with the slot antenna admittance Ya, which is simplified from the equivalent circuit of the transistor of FIG.

FIG. 16 is a plan view of an oscillator having a slot antenna designed in detail. As shown in the figure, an NDR-DCT channel having a width of 60 μm and a length of 4 μm is arranged at the center of a semiconductor substrate having a size of 1120 μm × 1120 μm. Two large conductive plates 3 and 13 connected to both ends are a source electrode and a drain electrode, and a slot antenna of the present invention is formed in a slit between these electrodes. In this case, the slot antenna body 2 has a width of 4 μm and a length of 720 μm, and the slit reflector portions 3 and 13 connected to the slot antenna body have the same dimensions, a width of 20 μm, and a length of 500 μm. In the vicinity of the active element, that is, in the vicinity of the feeding point, slit reflector portions 18 and 18 having a spacing of 60 μm and 15 μm × 15 μm are provided. Source, drain, and gate electrode pads, that is, wire bonding pads, are 100 μm square.
Note that Lg in the figure is the width of the gate provided across the channel of the semiconductor element, that is, the gate length (see FIG. 14), and the width of the slot antenna body 2 (the narrowness between the source and drain electrodes). The width of the gap) is sufficiently smaller than 4 μm.

  FIG. 17 is a diagram showing frequency characteristics of admittance corresponding to the oscillator of FIG. In FIG. 17, the horizontal axis represents frequency (THz), and the vertical axis represents admittance (S). In FIG. 17, the real part Re (Ya) and its imaginary part Im (Ya) of the admittance of the slot antenna, the real part Re (Yd) of the admittance when the Lg of NDR-DCT is 100 nm and 200 nm, and its imaginary part Im ( Yd). The simulation result shows that the oscillation condition is satisfied in the vicinity of the resonance frequency of the external resonator provided with the slot antenna designed according to the present invention, and oscillates with a margin in the power condition in the vicinity of 0.12 THz, that is, 120 GHz. .

  FIG. 18 is a plan view showing a pattern of another configuration of an oscillator having a slot antenna. The length of the slot antenna body 2 is 390 μm, and the dimensions of the slit reflector portions 3 and 13 connected to the slot antenna body 2 are the same as those of the oscillator shown in FIG. 16 except that the length is 300 μm. However, Lg of NDR-DCT is 100 nm.

FIG. 19 is a diagram showing the frequency characteristics of admittance corresponding to the oscillator of FIG. 18. The horizontal axis and vertical axis of FIG. 19 are the same as those of FIG.
As is apparent from FIG. 19, the oscillation condition is satisfied in the vicinity of the resonance frequency of the external resonator formed by the slot antenna designed according to the present invention, and oscillates with a margin in the power condition in the vicinity of 0.21 THz, that is, 210 GHz. The simulation results are as follows.

  FIG. 20 is a plan view showing a pattern of still another configuration of the oscillator having the slot antenna. The length of the slot antenna body is 270 μm, and the dimensions of the slit reflector portions 3 and 13 connected to the slot antenna body are the same as those of the oscillator shown in FIG. 16 except that the length is 200 μm. However, Lg of NDR-DCT is 100 nm.

FIG. 21 is a diagram showing the frequency characteristics of admittance corresponding to the oscillator of FIG. 20, and the horizontal axis and vertical axis of FIG. 21 are the same as those of FIG.
As is apparent from FIG. 21, the oscillation condition is satisfied in the vicinity of the resonance frequency of the external resonator formed by the slot antenna designed according to the present invention, and oscillates with a margin in the power condition in the vicinity of 0.305 THz, that is, about 305 GHz. This is a simulation result.

  From the above analysis results, it can be seen that the resonance frequency of the slot antenna changes almost in inverse proportion to the slot antenna length. Therefore, it can be seen that the oscillation frequency of the oscillation device can be controlled by the present invention.

  FIG. 22 shows the slot antenna shown in FIG. 20 without changing the design parameters, and the size of the electrodes constituting the slot antenna is changed. FIG. 23 shows the frequency characteristics of the admittance. As can be seen from FIG. 23, when compared with the frequency characteristics of the admittance shown in FIG. 21, the difference between the two is small and it can be seen that the oscillation condition is satisfied. In the simulation, the present invention has succeeded in localizing the electromagnetic field to the slot antenna body 2 sandwiched between the slit reflector portions 3 and 13, and the desired oscillation frequency is set without being influenced by the size of the entire device. It can be seen that it can be realized.

  FIG. 24 is a diagram illustrating a pattern in which the small slit reflector portion 18 is removed from the oscillator pattern illustrated in FIG. 20. FIG. 25 is a diagram showing the frequency characteristics of the admittance. As is clear from FIG. 25, the change in the characteristics is large compared with the frequency characteristics of the admittance shown in FIG. 21, and the oscillation condition that was satisfied in the case of the oscillator shown in FIG. 20 is no longer satisfied. I understand. In the simulation, the slit reflector portion 18 of the present invention has an effect of adjusting the degree of resonance rather than being merely a reflector, and has successfully localized the electromagnetic field to the slot antenna body 2. It can be seen that a desired oscillation frequency can be realized without being affected by the above.

Similarly to FIG. 24 for the structure of FIG. 20, FIG. 26 shows the case where the additional slit reflector 18 as described above is removed from the structure of FIG. 16, and FIG. 27 is a diagram showing the frequency characteristics of the admittance. is there.
As is clear from FIG. 27, in this case, the frequency satisfying the oscillation condition can be found as in FIG. 17, and it can be seen that the presence or absence of the small slit reflector 18 does not greatly affect the characteristics. This is an example in which a sufficient resonance circuit can be realized with only two sets of slit reflector portions 3 and 13 sandwiching the slot portion.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims. For example, the active element used and its oscillation frequency depend on the purpose. Needless to say, these are also included in the scope of the present invention.

  The antenna and the oscillator using the antenna of the present invention can be widely applied not only to devices that use terahertz electromagnetic waves for communication, measurement, calculation, etc., but also to circuits in general that are realized using electromagnetic wave transmission lines.

It is a figure which shows typically the structure of the slot antenna by this invention, (A) is a perspective view which shows the structure, (B) is a plane which shows a mode that AC power supply was connected to the feed part of the slot antenna of (A). FIG. It is a perspective view which shows typically the structure of the slot antenna which concerns on 2nd Embodiment by this invention. It is a perspective view which shows typically the structure of the 1st modification of the slot antenna which concerns on the 2nd Embodiment of this invention. It is a perspective view showing typically the composition of the 2nd modification of the slot antenna concerning a 2nd embodiment of the present invention. It is a perspective view which shows typically the structure of the 3rd modification of the slot antenna by this invention. It is a perspective view which shows typically one structural example of the array antenna using the slot antenna which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows typically the oscillator using the slot antenna by this invention. It is a perspective view which shows typically the oscillator using the slot antenna by this invention. It is a perspective view which shows typically the oscillator using the slot antenna by this invention. It is a perspective view which shows typically the oscillator using the slot antenna by this invention. It is a figure which shows the equivalent circuit of the oscillator of this invention. It is a figure which shows the outline of the frequency characteristic of the active element of the oscillator of this invention, and the admittance of a slot antenna, respectively, when (A) does not satisfy | fill oscillation conditions, (B) has shown the case where oscillation conditions are satisfy | filled. It is a perspective view which shows typically the specific example of the oscillator using the slot antenna by this invention. It is sectional drawing which shows the structure containing the active element in alignment with the AA of the oscillator shown in FIG. (A) shows an equivalent circuit of NDR-DCT, and (B) shows an equivalent circuit of an oscillator. It is a top view of an oscillator having a slot antenna designed in detail. It is a figure which shows the frequency characteristic of the admittance corresponding to the oscillator of FIG. It is a top view which shows the pattern of another structure of the oscillator which has a slot antenna. It is a figure which shows the frequency characteristic of the admittance corresponding to the oscillator of FIG. It is a top view which shows the pattern of another structure of the oscillator which has a slot antenna. It is a figure which shows the frequency characteristic of the admittance corresponding to the oscillator of FIG. It is a figure which shows the pattern which changed the size of the electrode which comprises it, without changing the design parameter of the slot antenna of FIG. It is a figure which shows the frequency characteristic of the admittance corresponding to the pattern of the oscillator of FIG. In the oscillator pattern shown in FIG. 20, it is a figure which shows the pattern of the oscillator except a small slit reflector part. It is a figure which shows the frequency characteristic of the admittance corresponding to the pattern of the oscillator of FIG. It is a figure which shows the pattern of the oscillator remove | excluding the additional slit reflector part from the structure of FIG. It is a figure which shows the frequency characteristic of the admittance corresponding to the pattern of the oscillator of FIG. It is a perspective view which shows the structure of the conventional slot antenna.

Explanation of symbols

1, 10, 15, 20, 25: Slot antenna 2: Slot antenna body 2A: Feed point 3: Slit reflector part (first slit reflector part)
3A, 3B: Air gaps 5, 11, 12: Conductive flat plates 6, 31: Substrate 13: Second slit reflector portions 14, 16, 18: Further slit reflector portions 30: Array antenna 32: Layer including active elements 33: Active elements 35, 40, 45, 50: Oscillator using slot antenna

Claims (10)

Two conductive plates arranged to form a slit at a predetermined interval;
The two conductive flat plates include two sets of slit reflector portions each having a gap formed in a direction perpendicular to the longitudinal direction of the slit,
A slot antenna, wherein the slits sandwiched between the two sets of slit reflector portions constitute a slot antenna body. The slot antenna according to claim 1 , wherein a slit reflector is further disposed on the conductive flat plate. The slot antenna according to claim 1 or 2 , wherein a slit reflector portion is disposed in the vicinity of a feeding point of the slot antenna body. Slot antenna according to any one of claims 1 to 3 by being arrayed, characterized in that it is configured as an array antenna, slot antenna. An oscillator comprising an active element and a slot antenna,
At least two electrodes of the active element are conductive plates,
The two conductive flat plates are arranged so as to form a slit at a predetermined interval,
The two conductive flat plates are provided with gaps to be at least two sets of slit reflector portions in a direction perpendicular to the longitudinal direction of the slit,
The oscillator, wherein the slits sandwiched between the two or more sets of slit reflector portions serve as a slot antenna body, and the slot antenna serves as both a resonator and an antenna. 6. The oscillator according to claim 5 , wherein a slit reflector is further disposed on the two conductive flat plates. 6. The oscillator according to claim 5 , further comprising a slit reflector disposed in the vicinity of a feeding point of the slot antenna body. The oscillator according to claim 5 , wherein the active element and the slot antenna are integrated on a substrate. The oscillator according to claim 5 or 8 , wherein the active element is a transistor or a negative resistance diode. The oscillator according to claim 8 , wherein an array type oscillator is configured by arranging a large number of the active elements and slot antennas on the substrate.