JP2003198259A - Self-heterodyne down converter circuit, millimeter-wave video transmission system including the circuit, and heterojunction bipolar transferred electron device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-heterodyne down converter circuit with a simple circuit composition and proper characteristics, provided to a receiver which receives a high-frequency signal and a local oscillation signal transmitted by radio. <P>SOLUTION: A heterojunction bipolar transferred electron device (HBTED) 17 for generating an intermediate frequency signal (IF signal) in a frequency band which is lower than the high-frequency signal (RF signal) from signals, based on the high-frequency signal received and the local oscillation signal (LO signal) received is provided. This HBTED 17 operates in a oscillator-mixer mode or an amplifier-mixer mode according to a bias condition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-heterodyne down-converter circuit, and more particularly, to a self-heterodyne down-converter using a heterojunction bipolar transfer electron device (hereinafter abbreviated as "HBTED"). Related to the circuit.

The present invention also relates to a millimeter wave video transmission system using such a self-heterodyne down converter circuit as a receiver.

The present invention also relates to a HBTED suitable as a component of such a circuit having a function of self-heterodyne down conversion and / or a millimeter wave band receiver.

[0004]

2. Description of the Related Art Japanese Patent Laid-Open No. 2001-53640 discloses
As shown in FIG. 11, a transmitter transmits a modulated signal (RF
Signal) 111 and local oscillation signal (LO signal) 112
Has been disclosed, and a receiver that has received these signals has disclosed a wireless communication system in which self-heterodyne down-conversion is performed using a squarer to obtain an intermediate frequency signal (IF signal) 113. Further, the publication describes a wireless communication system using a self-heterodyne down-converter circuit using a bandpass filter, an injection locking oscillator (or a single tuning amplifier) and a mixer, instead of the squarer. There is.

[0005]

By the way, in general, when performing self-heterodyne, the bandwidth of the received RF signal (RFmax-RFmin) is equal to the minimum RF frequency and LO.
It is desirable to be narrower than the frequency difference (RFmin-LO). However, this condition cannot be satisfied when transmitting and receiving a signal with a wide bandwidth such as a millimeter wave band communication system. Therefore, as shown in FIG.
The signal 111 in the RF band is self-mixed, and an unnecessary signal component (the minimum frequency is zero, the required IF signal 11
114) (having the same bandwidth as the bandwidth of 3). Here, when performing the self-heterodyne down-conversion using the squarer as described above, the power of the LO signal 112 is about the same as the power of the RF signal 111, and therefore the power of the unnecessary signal component 114 in the IF band is required. The power of the IF signal 113 becomes so large that it cannot be ignored, which is a problem.

On the other hand, the receiving circuit using the bandpass filter, the injection locked oscillator and the mixer has a complicated structure.
There is a problem that the unit price is high and it is difficult to adjust the LO band matching impedance between the components.

Therefore, an object of the present invention is to provide a self-heterodyne down converter circuit having a simple circuit configuration and excellent characteristics.

Another object of the present invention is to provide a millimeter wave video transmission system using such a self-heterodyne down converter circuit as a receiver.

Another object of the present invention is to provide an HBTED suitable as a component of such a self-heterodyne down converter circuit.

[0010]

In order to solve the above problems, the self-heterodyne down-converter circuit of the present invention uses a radio frequency signal (hereinafter referred to as "RF signal") and a local oscillation signal (hereinafter referred to as "LO"). "Signal.")
A self-heterodyne down converter circuit provided in a receiver for receiving a signal, the intermediate frequency of a frequency band lower than the RF signal from a signal based on a received RF signal and a signal based on a received LO signal. It is characterized by including HBTED for generating a signal (hereinafter referred to as “IF signal”).

Here, "HBTED" (heterojunction bipolar transfer electron device) is an integrally formed three-terminal type or four-terminal type element. Three
The terminal type is also called a heterojunction bipolar gantry device, and the 4-terminal type is also called a 4-terminal heterojunction bipolar gun device.

According to the self-heterodyne down-converter circuit of the present invention, the HBTED is an IF signal whose frequency band is lower than that of the RF signal from the signal based on the received RF signal and the signal based on the received LO signal. To generate. By using HBTED, self-heterodyne down-conversion becomes possible with a simple circuit configuration. The point that the characteristics are improved will be described later.

In the self-heterodyne down converter circuit of one embodiment, a signal based on the LO signal is
The HBTED is a signal obtained by internally amplifying the signal by the transferred electron effect. In this self-heterodyne down converter circuit,
The HBTED performs a function of amplifying the LO signal by the transferred electron effect and a function of mixing the amplified LO signal with a signal based on the RF signal to generate an IF signal. HBTED like this
This operation mode is called "amplifier / mixer mode".

In the self-heterodyne down converter circuit of one embodiment, a signal based on the LO signal is
It is characterized in that the HBTED is a signal which is injection-locked and oscillated internally by the transferred electron effect in response to a signal. In this self-heterodyne down-converter circuit, HBTED has a function of receiving an LO signal and performing injection locking oscillation by the transferred electron effect, and mixing the injection locking oscillation LO signal with a signal based on the RF signal to generate an IF signal. Executes the function to generate. Such an operation mode of HBTED is called “oscillator / mixer mode”.

The HBTED has the following functions (1) to (4) in the high frequency band, especially in the millimeter wave band. The fourth function (amplifier / mixer mode)
Is a feature we recently discovered. (1) Function to oscillate in millimeter wave band (oscillator mode) (2) Function to oscillate in millimeter wave band and mix (up-convert or down-convert) with input signal (oscillator / mixer mode) (3) Input millimeter Function for amplifying waveband signal (amplification mode) (4) Function for single tuning amplification of input millimeter waveband signal and mixing (up-conversion or down-conversion) with another input signal (amplifier / mixer mode) )

For HBTED, the physics of oscillator / mixer mode operation and the physics of amplifier / mixer mode operation are particularly complex. The mechanism of oscillation and amplification is the transferred electron effect, and it becomes possible to mix by the current dependence of the transferred electron effect. As will be described later, for HBTED having a properly designed structure, particularly for HBTED in which the gradation of the doping concentration of the active layer is properly set,
By applying a bias current or a bias voltage within a predetermined range, both the oscillator / mixer mode operation and the amplifier / mixer mode operation described above are possible.

FIGS. 1 and 2 exemplify a mode in which HBTEDs 17 and 27 are provided in the receiver self-heterodyne down converter circuit in a cathode ground type and a base ground type, respectively. When the grounded cathode HBTED 17 in FIG. 1 or the grounded base HBTED 27 in FIG. 2 operates in the oscillator / mixer mode, equivalent functions such as the bandpass filter 34, the oscillator 35, the mixer 36 and the IF signal amplifier 37 shown in FIG. Show.

In the oscillator / mixer mode, the LO signal and the RF signal are received by the receiving antenna 31, amplified by the low noise amplifier 32, and input to the input terminal of the HBTED 33. The current and voltage bias of the HBTED 33 are set so that the HBTED 33 oscillates, and its oscillation frequency mainly depends on the thickness of the active layer of the HBTED 33 and the output impedance. The HBTED 33 and the output circuit are designed in advance so that the oscillation frequency thereof is substantially the same as the frequency of the LO signal received. HBTED33
When the LO signal enters the input terminal of, the LO signal changes to HBTED
Since the oscillation frequency of 33 is injection-locked, the frequency and phase of the oscillation signal are the same as those of the LO signal which is the input signal.

At the same time, the RF signal that enters the input terminal of the HBTED33 is mixed with the oscillation signal by the non-linear transfer electron effect, and the I signal enters the inside of the HBTED33.
The F signal appears. At the low frequency of this IF signal, HB
Since the TED 33 operates as a normal transistor like the IF signal amplifier 37, the IF signal is amplified.

In this way, the HBTED exhibits the equivalent function as shown in FIG. 3 in the oscillator / mixer mode.
In order to operate the HBTED in the oscillator / mixer mode, it is necessary to set the bias current and voltage such that oscillation due to the transferred electron effect easily occurs.

If the bias current or bias voltage of the HBTED is out of the oscillation range, oscillation does not occur, but amplification can be performed in the same region as the oscillation frequency. Cathode grounded HBTED of FIG. 1 and base grounded HBT of FIG.
When the ED operates in the amplifier / mixer mode, it exhibits equivalent functions such as the bandpass filter 44, the amplifier 45, the mixer 46 and the IF signal amplifier 47 shown in FIG.

In the amplifier / mixer mode, the LO signal and the RF signal are received by the receiving antenna 41, amplified by the low noise amplifier 42, and input to the input terminal of the HBTED 43. The HBTED 44 is set to a bias current and voltage so as to amplify a single frequency without oscillating. The frequency to be amplified depends on the thickness of the active layer of the HBTED 44 and the output impedance of the circuit. The HBTED 44 and the output circuit are designed in advance so that the amplification factor of the LO signal is higher than that of the RF signal. By designing in this way, the LO signal that enters the input terminal of the HBTED 44 is amplified. The RF signal entering the input terminal of the HBTED 44 is not amplified, but is mixed with the amplified LO signal and the nonlinear transfer electron effect to generate an IF signal. Since this IF signal has a low frequency, HBTE
D44 is an IF signal amplifier 47 as a normal transistor.
The IF signal is amplified.

In this way, the HBTED and the amplifier / mixer mode HBTED have the equivalent functions as shown in FIG. The operation in the amplifier / mixer mode has the advantage of being less dependent on the bias condition and the output circuit impedance than the operation in the oscillator / mixer mode.

The amplifier / mixer mode HBTED is a device for mixing current. Since the output power of the IF signal is the product of the LO signal current and the RF signal current flowing in the active layer, it is important that the current amplification factor at the LO signal frequency is high. Furthermore, it is important that the current amplification factor at the frequency of the LO signal is higher than the current amplification factor at the frequency of the RF signal so that the signals in the RF band do not self-mix and produce unnecessary signal components in the IF band. is there.

FIG. 5 shows the characteristic measurement result of the current amplification factor vs. frequency for the single base grounded HBTED. It should be noted that this HBTED has a bias current and voltage for performing amplification mode operation by the transferred electron effect. As can be seen from FIG. 5, this current amplification characteristic has a steep peak at the frequency f0 = 58 GHz. If the peak frequency of this current amplification characteristic is f0, the saturation speed of electrons is Vsat, and the thickness of the active layer is x,
These relational expressions are represented by f0 = Vsat / x. The material of the HBTED active layer is GaAs (electron saturation velocity is Vsat = 10 ⁷ cm · s ⁻¹ ), the thickness of the active layer is 1.7 μm, and the peak of current amplification occurs at about 58 GHz. This HBTED characteristic is optimal for application to self-heterodyne downconverter circuits because the amplification factor at frequencies away from f0 is low.

FIG. 6 shows a single cathode grounded HB that performs self-heterode down conversion in the amplifier / mixer mode.
The conversion loss vs. frequency characteristic measurement result about TED is shown. In this measurement, the power of the input LO signal is-
The frequency of the LO signal is set to 59.01 GHz at 20 dBm or -30 dBm. The input RF signal is
The power was the same as the LO signal and the frequency was swung from 59.4 GHz to 62.6 GHz. This HBTED amplifies the LO signal, mixes the amplified LO signal with the RF signal, and amplifies the generated IF signal.
The frequency of the generated output IF signal is from 0.39 GHz to 3.69 GHz. Input LO signal power and R
Although the power of the F signal is low, the conversion loss of this HBTED is low. As described above, according to the self-heterodyne down converter circuit of the present invention, good characteristics can be obtained.

The above-mentioned measurement results are for a single HBTED, and the input circuit and the output circuit are not added to the input terminal and the anode terminal of the HBTED. However, since the HBTED is a device that mixes current, the LO signal current and R
It is preferable to add an input circuit to maximize the F signal current. Therefore, in the self-heterodyne down converter circuit of one embodiment, the signal power input to the HBTED becomes high in the frequency band of the LO signal,
A passive circuit (16, 26, 7) is connected to the input terminal of the HBTED.
6, 86, 96) are connected.

As for the output circuit, it is desirable that the current amplification factor be high in the frequency band of the IF signal. Furthermore, in order to further improve the conversion loss, an output circuit impedance that maximizes the IF output power is desirable. Therefore, the self-heterodyne down-converter circuit of one embodiment is configured so that the signal power output from the HBTED is high in the frequency band of the IF signal.
A passive circuit (19, 29, 79, 8) is connected to the anode terminal of the ED.
9, 99) are connected.

The output circuit attached to the HBTED preferably has an impedance of almost zero ohm with respect to the frequency band of the LO signal. Therefore, the self-heterodyne down-converter circuit of one embodiment has a passive circuit (18, 28, 711, 11) at the anode terminal of the HBTED so that the output impedance of the HBTED is substantially zero in the frequency band of the LO signal. 712
88, 98) are connected.

The output circuit impedance may be almost zero ohms in the frequency band of the LO signal, and the output circuit impedance may be almost infinite in the frequency band of the double wave of the LO signal. By doing this, L
It is possible to suppress the second harmonic of the IF signal generated due to the second harmonic of the O signal. Therefore, in the self-heterodyne down converter circuit of one embodiment, the output impedance of the HBTED is substantially zero in the frequency band of the LO signal, and the output impedance of the HBTED is in the frequency band of the second harmonic of the LO signal. The passive circuit (711, 712) is connected to the anode terminal of the HBTED so as to be substantially infinite.

The bias range for the HBTED to operate in the oscillator / mixer mode is relatively narrow, and the bias range for the amplifier / mixer mode to operate is relatively wide. The HBTED can operate as a normal transistor even if the bias current or voltage is out of the range for the transfer electron effect to occur. The HBTED, which operates as an ordinary transistor, can be used as an IF band amplifier.

In order to operate the HBTED as an ordinary transistor, it is possible to set the dimensions of the HBTED so that the transferred electron effect is unlikely to occur. Reference "Demonstrationofa77-GHzHeter
ojunctionBipolarTransferredElectronDevice "(JKTw
ynam, M. Yagura, N. Takahashi, E. Suematsu, and H. Sat
o, IEEE Electron Device Lett. 21 (01), pp.2-4, 200
0), JP-A-2001-077444, the specification or drawings of Japanese Patent Application No. 2001-078528, as described in JP-A-2001-284682, because of the current spreading effect,
A special doping gradation is required for the active layer of HBTED. The optimum cathode width of HBTED depends on the degree of doping gradation of the active layer.
For example, a device in which the cathode width is very narrow compared with the optimum width may not operate as a transferred electron effect and may operate as a normal transistor. On the other hand, even if the width of the cathode is much wider than the optimum width, the transferred electron effect does not occur,
It may operate as an ordinary transistor. For example, a device with a cathode width much narrower than the optimum width,
It can also be used as a low noise amplifier for amplifying the input signal of HBTED. Since the device having a narrow cathode width has good high frequency characteristics, it is desirable to use it as a low noise amplifier.

When embodying the self-heterodyne down-converter circuit of the present invention, the HBTED and the passive circuits described above are integrally formed on the same semiconductor substrate in order to increase the operating efficiency and reduce the cost. It is desirable that

Similarly, a passive circuit such as a self-heterodyne down converter circuit including the HBTED and an active circuit (IF band amplifier or low noise amplifier) including a transistor having the same layer structure as the HBTED layer structure are provided.
It is desirable that they are integrally formed on the same semiconductor substrate. This is because the passive circuit and the active circuit can be manufactured at the same time by the same process, and thus the receiver used in the millimeter wave band communication system can be manufactured at low cost.

It is necessary to design the above HBTED structure according to the frequency of the LO signal actually used in the communication system. The HBTED can be operated in a wide frequency range by changing the thickness of the active layer of the HBTED and the composition of the semiconductor material. Lower frequency and higher frequency operation is not impossible, but the LO signal frequency of the preferred communication system of the present invention is from 30 GHz to 12 GHz.
Up to 0 GHz. Furthermore, the LO frequency range of the most desirable communication system is GaAsMMIC, which has a low cost.
The range is from 55 GHz to 85 GHz, which can be produced by technology.

H using various III-V compound semiconductors
BTED can be manufactured (eg, GaA
s, InGaAs, InP, GaN, etc.). HBTED
Is preferably formed on a semi-insulating GaAs substrate, and the active layer of HBTED is GaAs, which is a millimeter-wave technology with low cost and high performance.
Suitable for mass production. In other words, such HBTED
Is smaller than a millimeter-wave band active device (millimeter-wave transistor or the like), easy to manufacture, and low in cost.

Self-heterodyne down with RF and LO signals transmitted wirelessly from the transmitter, these signals received by the receiver, at which receiver the amplifier / mixer mode HBTED or oscillator / mixer mode HBTED described above is provided. A communication system that generates an IF signal by a converter circuit, for example, a millimeter wave band video transmission system such as a television is established. According to such a communication system, a wide IF bandwidth, specifically, an IF bandwidth in which the maximum frequency is twice or more higher than the minimum frequency can be practically used. Moreover, since the conversion efficiency of the HBTED circuit is high, the power consumption of the receiver can be reduced.

The input impedance of this kind of HBTED is required to be high. So, this invention
At least an anode layer, an active layer, a base layer, a cathode graded layer, a cathode layer, a cathode ballast layer, a cathode ballast graded layer, and a cathode cup layer were sequentially provided on a semi-insulating substrate. HBTE
In D, the cathode graded layer, the cathode layer, the cathode ballast layer, the cathode ballast graded layer, and the cathode cup layer have a circular pattern shape having an area smaller than that of the base layer. Circular cathodes can be made smaller than known elongated rectangular cathodes. Therefore, the input impedance can be easily increased. The circular cathode is required to suppress the doping gradation (current spreading effect and stable transfer electron effect) of the active layer. If the area is small, the degree of doping gradation is high. Required) can be relatively low for a small area. Thereby, the transferred electron effect can be stably generated, and the HBTED can be easily operated in the amplifier / mixer mode or the oscillator / mixer mode. Therefore, the HBTED having a circular cathode is suitable as a component of a self-heterodyne converter circuit of a millimeter-wave band receiver.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

(First Embodiment) FIG. 1 shows a self-heterodyne down-converter circuit 15 of a receiver with a grounded cathode H.
3 illustrates an embodiment with a BTED17. This self-heterodyne down conversion circuit 15 is generally referred to as a wirelessly transmitted signal (LO signal and RF signal) 12.
In response, the IF signal 11 of a frequency band lower than the RF signal is received.
Outputs 0. The grounded cathode HBTED17 is an amplifier
Bias conditions are set to operate in mixer mode.

More specifically, a transmission signal 12 consisting of an LO signal and an RF signal is transmitted from the transmission antenna 11 of the transmitter,
The signal is received by the receiving antenna 13 of the receiver. LO signal and R
The F signal is amplified by the low noise amplifier 14 and enters the self-heterodyne down converter circuit 15. LO that enters the cathode grounded HBTED 17 under the influence of the input matching circuit 16
The power of the signal and the RF signal can be increased. This LO signal is amplified by the transferred electron effect inside the grounded cathode HBTED17. Furthermore, inside the grounded cathode HBTED17, this amplified L
The O signal and the RF signal are mixed to generate an IF signal in a frequency band lower than that of the RF signal. The generated IF signal is amplified by the transistor operation of the grounded cathode HBTED 17. Λ / 4 open stub 18 of output circuit (length is 1/4 of the wavelength of LO signal frequency
Is set to. ), The LO signal current in the HBTED active layer is maximized, and the LO signal is not so much output from the self-heterodyne down-conversion circuit 15. Further, the power of the output IF signal 110 can be increased due to the influence of the output IF matching circuit 19.

In this embodiment, the LO signal frequency is 5
At 9.01 GHz, the RF signal frequency is 59.4 GHz-
At 62.5 GHz, the IF signal frequency is 0.39 GHz-
3.49 GHz. Bandwidth of IF signal is 3.1GH
Since z is higher than the lowest frequency of 0.39 GHz of IF, it is important that the LO signal has a high amplification factor. As shown in FIG. 11 regarding the conventional technique, if the power of the LO signal 112 to be mixed is about the same as the power of the RF signal 111, the power of the unnecessary signal component 114 in the IF band with respect to the power of the necessary IF signal 113. It becomes too big to ignore and becomes a problem. On the other hand, in the present embodiment, as shown in FIG.
O signal (amplified inside HBTED17) 12
Since the power of 2 is larger than the power of the RF signal 121, the power of the necessary IF signal 123 exceeds the power of the unnecessary signal component 124 in the IF band, and the unnecessary signal component 124 in the IF band does not matter.

The cathode of the HBTED 17 has an elongated rectangular pattern shape, the cathode width is 4 μm, and the cathode length is 20 μm. The active layer of HBTED17 is G
It is made of aAs and has a thickness of 1.7 μm and is doped. The doping concentration of the active layer depends on N at the anode interface.
_D = 1.7 × 10 ¹⁶ cm ⁻³ to N _D at base interface = 3 × 1
There is a gradation of up to 0 ¹⁶ cm ^-3 . This HBTED
The structure of 17 will be described in detail later.

The λ / 4 open stub 18 is designed so that the output circuit impedance is almost zero ohms with respect to the frequency of the LO signal. Input matching circuit 1
The 6 and λ / 4 open stubs 18 are made of conventional microstrip or coplanar lines. The output IF matching circuit 19 is made up of an MMIC capacitor and an inductor.

(Second Embodiment) FIG. 2 shows a base-grounded HB in a self-heterodyne down converter circuit 25 of a receiver.
3 illustrates an embodiment with a TED 27. This self-heterodyne down conversion circuit 25 is generally referred to as a wirelessly transmitted signal (LO signal and RF signal) 22.
In response, the IF signal 21 of a frequency band lower than the RF signal is received.
Outputs 0. The bias condition of the grounded base HBTED 27 is set so as to operate in the amplifier / mixer mode.

More specifically, a transmission signal 21 composed of an LO signal and an RF signal is transmitted from the transmission antenna 21 of the transmitter,
The signal is received by the receiving antenna 23 of the receiver. LO signal and R
The F signal is amplified by the low noise amplifier 24 and enters the self-heterodyne down conversion circuit 25. Due to the influence of the input matching circuit 26, the power of the LO signal and the RF signal entering the grounded base HBTED 27 can be increased. This LO signal is
It is amplified by the transferred electron effect inside the base ground HBTED 27. Further, inside the grounded base HBTED 27, the amplified LO signal and the RF signal are mixed, and an IF signal in a frequency band lower than the RF signal is generated. The generated IF signal is generated by the transistor operation of the base ground HBTED27.
Is amplified. Output circuit λ / 4 open stub 28
(The length is set to 1/4 with respect to the wavelength of the LO signal frequency.) The LO signal current in the HBTED active layer is maximized due to the influence of the LO signal, and the LO signal is self-heterodyne down-converted too much. It is not output from the circuit 25. In addition, the output IF signal 21 is affected by the output IF matching circuit 29.
The power of 0 can be increased.

In this embodiment, the LO signal frequency is 5
At 9.01 GHz, the RF signal frequency is 59.4 GHz-
At 62.5 GHz, the IF signal frequency is 0.39 GHz-
3.49 GHz. Bandwidth of IF signal is 3.1GH
Since z is higher than the lowest frequency of 0.39 GHz of IF, it is important that the LO signal has a high amplification factor. In the present embodiment, as shown in FIG. 12, the power of the LO signal (amplified inside the HBTED 27) 122 to be mixed is larger than the power of the RF signal 121, so that the power of the necessary IF signal 123 is in the IF band. The power of the unnecessary signal component 124 of 1 is greatly exceeded, and the unnecessary signal component 124 of the IF band does not become a problem.

The cathode of HBTED27 has an elongated rectangular pattern shape, the cathode width is 5 μm, and the cathode length is 30 μm. The active layer of HBTED27 is G
It is made of aAs and has a thickness of 1.7 μm and is doped. The doping concentration of the active layer depends on N at the anode interface.
_D = 1.3 × 10 ¹⁶ cm ⁻³ to N _D at base interface = 2 × 1
There is a gradation of up to 0 ¹⁶ cm ^-3 . This HBTED
The structure of 27 will be described later in detail.

The input matching circuit 26 and the λ / 4 open stub 28 are made of ordinary microstrip lines or coplanar lines. The output IF matching circuit 29 is an MMIC
Made of capacitors and inductors for.

(Third Embodiment) FIG. 7 shows a self-heterodyne down-converter circuit 75 of a receiver with a grounded cathode H.
7 illustrates an embodiment with a BTED77. This self-heterodyne down conversion circuit 75 is generally referred to as a wirelessly transmitted signal (LO signal and RF signal) 72.
In response, the IF signal 71 of a frequency band lower than the RF signal is received.
Outputs 0.

More specifically, a transmission signal 72 consisting of an LO signal and an RF signal is transmitted from the transmission antenna 71 of the transmitter,
The signal is received by the receiving antenna 73 of the receiver. LO signal and R
The F signal is amplified by the low noise amplifier 74 and enters the self-heterodyne down converter circuit 75. LO which enters the cathode grounded HBTED 77 under the influence of the input matching circuit 76
The power of the signal and the RF signal can be increased. This LO signal is amplified by the transferred electron effect inside the grounded cathode HBTED77. Furthermore, inside the grounded cathode HBTED77, this amplified L
The O signal and the RF signal are mixed to generate an IF signal in a frequency band lower than that of the RF signal. The generated IF signal is amplified by the transistor operation of the grounded cathode HBTED77. Output circuit λ / 8 transmission line 71
The LO signal current in the HBTED active layer is maximized by the influence of 1 and the λ / 8 open stub 712 (both of which are set to 1/8 in length with respect to the wavelength of the LO signal frequency). The LO signal is not output so much from the self-heterodyne down conversion circuit 75. Furthermore, λ / 8
Due to the influence of the transmission line 711 and the λ / 8 open stub 712, the current of the second harmonic of the LO signal is suppressed, and the second harmonic of the IF signal is hardly generated. Further, the output IF matching circuit 79
Due to the influence of, the power of the output IF signal 710 can be increased.

In this embodiment, the LO frequency is 59.0.
At 1 GHz, RF frequency is 59.4 GHz-62.5G
IF frequency is 0.39 GHz-3.49 GHz in Hz
Is. The bandwidth of the IF signal is 3.1 GHz, and I
Since it is higher than the lowest frequency of the F signal, 0.39 GHz,
It is important that the LO signal has a high amplification factor. In the present embodiment, as shown in FIG.
Signal (amplified inside HBTED77) 122
Since the power of is larger than the power of the RF signal 121,
The power of the required IF signal 123 is the unnecessary signal component 1 in the IF band
Greater than the power of 24, the unwanted signal component 124 in the IF band does not matter.

The bias condition of the cathode grounded HBTED 77 is set so as to operate in the amplifier / mixer mode. The cathode of HBTED77 has an elongated rectangular pattern shape, the cathode width is 4 μm, and the cathode length is 20 μm. HBTED77 active layer is GaAs
The thickness is 1.7 μm and is doped. For the doping concentration of the active layer, N _D = 1.
From 7 × 10 ¹⁶ cm ⁻³ to N _D at the base interface = 3 × 10 ¹⁶ cm
^-There are gradations up to ^-3 . The structure of this HBTED77 will be described in detail later.

The input matching circuit 76, the λ / 8 transmission line 711 and the λ / 8 open stub 712 are made of ordinary microstrip lines or coplanar lines. Output I
The F matching circuit 79 is made of an MMIC capacitor and an inductor.

(Fourth Embodiment) FIG. 8 shows a self-heterodyne down-converter circuit 85 of the receiver having a grounded cathode H.
9 illustrates an embodiment with a BTED 87. The self-heterodyne down conversion circuit 85 is generally referred to as a wirelessly transmitted signal (LO signal and RF signal) 82.
In response, the IF signal 81 in the frequency band lower than the RF signal is received.
Outputs 0. The grounded cathode HBTED87 is an amplifier
Bias conditions are set to operate in mixer mode.

More specifically, a transmission antenna 81 of the transmitter transmits a transmission signal 82 composed of an LO signal and an RF signal, which is received by a reception antenna 83 of the receiver. The LO signal and RF signal are amplified by the low noise amplifier 84 and enter the self-heterodyne down-conversion circuit 85. Due to the influence of the input matching circuit 86, the LO signal and RF signal power entering the cathode grounded HBTED 87 can be increased. This LO signal is amplified by the transferred electron effect inside the cathode grounded HBTED 87. Further, inside the grounded cathode HBTED87, this amplified L
The O signal and the RF signal are mixed to generate an IF signal in a frequency band lower than that of the RF signal. The generated IF signal is amplified by the transistor operation of the cathode grounded HBTED 87. L in the HBTED active layer is affected by the λ / 4 open stub 88 of the output circuit (the length is set to 1/4 with respect to the wavelength of the LO signal frequency).
The O signal current is maximized, and the LO signal is not output so much from the self-heterodyne down-conversion circuit 85. The output IF signal 81 is affected by the output IF matching circuit 89.
The power of 0 can be increased. The IF signal is further amplified by the influence of the IF amplifier 813 provided in the subsequent stage of the output IF matching circuit 89. Therefore, the output IF signal 81
The power of 0 can be increased.

In this embodiment, the LO frequency is 59.0.
At 1 GHz, RF frequency is 59.4 GHz-62.5G
IF frequency is 0.39 GHz-3.49 GHz in Hz
Is. The bandwidth of the IF signal is 3.1 GHz, and I
Since it is higher than the lowest frequency of the F signal, 0.39 GHz,
It is important that the LO signal has a high amplification factor. In the present embodiment, as shown in FIG.
Signal (amplified inside HBTED87) 122
Since the power of is larger than the power of the RF signal 121,
The power of the required IF signal 123 is the unnecessary signal component 1 in the IF band
Greater than the power of 24, the unwanted signal component 124 in the IF band does not matter.

The cathode of HBTED87 has an elongated rectangular pattern shape, the cathode width is 4 μm, and the cathode length is 20 μm. The active layer of HBTED87 is G
It is made of aAs and has a thickness of 1.7 μm and is doped. The doping concentration of the active layer depends on N at the anode interface.
_D = 1.7 × 10 ¹⁶ cm ⁻³ to N _D at base interface = 3 × 1
There is a gradation of up to 0 ¹⁶ cm ^-3 . This HBTED
The structure of 87 will be described in detail later.

The IF amplifier 813 is composed of a transistor having the same layer structure as that of the HBTED 87.
This transistor is integrally formed with the HBTED 87 on the same semiconductor substrate by the same manufacturing process. In other words, this transistor uses HBTED under a bias condition such that the transferred electron effect does not occur.

The input matching circuit 86 and the λ / 4 open stub 88 are made of ordinary microstrip lines or coplanar lines. The output IF matching circuit 89 is an MMI
It is made of a capacitor for C and an inductor.

(Fifth Embodiment) FIG. 9 shows a self-heterodyne down-converter circuit 95 of the receiver having a grounded cathode H.
7 illustrates an embodiment with a BTED 97. This self-heterodyne down conversion circuit 95 is, generally speaking, a signal (LO signal and RF signal) 92 transmitted by radio.
In response, the IF signal 91 of a frequency band lower than the RF signal is received.
Outputs 0. The grounded cathode HBTED97 is an oscillator
Bias conditions are set to operate in mixer mode.

More specifically, a transmission signal 92 consisting of an LO signal and an RF signal is transmitted from the transmission antenna 91 of the transmitter,
The signal is received by the receiving antenna 93 of the receiver. LO signal and R
The F signal enters the self-heterodyne down conversion circuit 95 and is amplified by the low noise amplifier 914 in the first stage. Cathode grounded HBTED due to input matching circuit 96
The LO signal and RF signal power entering 97 can be increased. The cathode grounded HBTED 97 that receives this LO signal internally performs injection locking oscillation by the transferred electron effect to generate an LO signal. Cathode ground HBTED
Inside 97, this injection-locked LO signal and RF
The signal and the signal are mixed to generate an IF signal in a frequency band lower than that of the RF signal. The generated IF signal is amplified by the transistor operation of the grounded cathode HBTED97. Output circuit λ / 4 open stub 98 (LO
The length is set to 1/4 of the wavelength of the signal frequency. ), The LO signal current in the HBTED active layer is maximized, and the LO signal is not output so much from the self-heterodyne down conversion circuit 95. Moreover, the power of the output IF signal 910 can be increased due to the influence of the output IF matching circuit 99.

In this embodiment, the LO frequency is 59.0.
At 1 GHz, RF frequency is 59.4 GHz-62.5G
IF frequency is 0.39 GHz-3.49 GHz in Hz
Is. The bandwidth of the IF signal is 3.1 GHz, and I
Since it is higher than the lowest frequency of the F signal, 0.39 GHz,
It is important that the LO signal has a high amplification factor. In the present embodiment, as shown in FIG.
Signal (amplified inside HBTED97) 122
Since the power of is larger than the power of the RF signal 121,
The power of the required IF signal 123 is the unnecessary signal component 1 in the IF band
Greater than the power of 24, the unwanted signal component 124 in the IF band does not matter.

The cathode of HBTED97 has an elongated rectangular pattern shape, the cathode width is 4 μm, and the cathode length is 20 μm. The active layer of HBTED97 is G
It is made of aAs and has a thickness of 1.7 μm and is doped. The doping concentration of the active layer depends on N at the anode interface.
_D = 1.7 × 10 ¹⁶ cm ⁻³ to N _D at base interface = 3 × 1
There is a gradation of up to 0 ¹⁶ cm ^-3 . This HBTED
The structure of 97 will be described in detail later.

The low noise amplifier 914 is composed of a transistor having the same layer structure as that of the HBTED97. This transistor is integrally formed with the HBTED 87 on the same semiconductor substrate by the same manufacturing process.
In other words, this transistor uses HBTED under a bias condition such that the transferred electron effect does not occur. This transistor has a cathode width of 1 μm and a cathode length of 5 μm. With this size, the transferred electron effect does not occur.

The input matching circuit 96 and the λ / 4 open stub 98 are made of ordinary microstrip lines or coplanar lines. The output IF matching circuit 99 is an MMI
It is made of a capacitor for C and an inductor.

(Sixth Embodiment) FIG. 10 shows the self-heterodyne down-converter circuit of the present invention in a millimeter-wave band receiver 1.
10 schematically shows an embodiment of a 60-GHz band domestic millimeter-wave video transmission system built in 08.

In this embodiment, the BS / CS provided on the roof of the house 101 is the broadcast / communication signal 102 from the BS (broadcast satellite) and / or CS (communication satellite) of Japan.
It is received by the antenna 103. The BS / CS antenna 1
03 through a cable to millimeter-wave band up converter 10
4 is connected. This millimeter wave band up converter 1
04 uses the received broadcast / communication signal 102 as an IF signal and up-converts it using the LO signal of 59.01 GHz to generate an RF signal in the millimeter wave band. This millimeter-wave band RF signal, together with the LO signal of 59.01 GHz,
It is wirelessly transmitted from the millimeter-wave band transmission antenna 105 into the house 101.

Normal television receivers 109 are arranged at various places in the house 101. A millimeter-wave band receiver 108 having a built-in self-heterodyne down converter circuit and a millimeter-wave band receiving antenna 107 are connected to each television receiver 109 via a cable. A signal (millimeter wave band RF signal and LO signal) 106 transmitted from the millimeter wave band antenna 105 is a millimeter wave band receiving antenna 107.
To be received. Then, the millimeter-wave band receiver 108 down-converts the millimeter-wave band RF signal using the self-heterodyne down-converter circuit of the present invention, and BS and CS
The original IF signal of is reproduced. With this, each TV receiver 1
All BS and CS signals come into 09, and channel selection becomes free.

According to such a communication system, a wide I
Even an F bandwidth, specifically, an IF bandwidth whose maximum frequency is twice or more higher than the minimum frequency can withstand practical use.
Moreover, since the conversion efficiency of the HBTED circuit is high, the power consumption of the receiver can be reduced. Further, due to the high-performance operation of HBTED, most of the circuits of the receiver 108 are manufactured on an integrated semiconductor substrate, so that the manufacturing cost is low.

(Seventh Embodiment) FIG. 14 shows a sectional structure of an HBTED used in each of the above-described embodiments.
The HBTED cathode has an elongated rectangular pattern shape, the cathode width is 4 μm, and the cathode length is 20 μm.
It is set to μm.

Specifically, this HBTED is obtained by forming a GaAs anode layer (thickness: 50) on a semi-insulating GaAs substrate 141.
0 nm, donor doping concentration N _D = 5 × 10 ¹⁸ cm
^-3 ) 142 is provided. This GaAs anode layer 14
Some of the area on the 2, In _{0. 49} Ga _0.51 P anode layer (a thickness of 20 nm, the doping concentration of donor N _D = 3 × 1
0 ¹⁸ cm ^-3 ) 143 and a GaAs active layer (thickness 1700
nm, donor doping concentration N _D = 1.4 × 10 ¹⁶ c
m ⁻³ → 3 × 10 ¹⁶ cm ⁻³ ) 144 and a GaAs base layer (thickness 150 nm, acceptor doping concentration N _A =)
4 × 10 ¹⁹ cm ⁻³ ) 145 are laminated in the same pattern in this order. Furthermore, this GaAs base layer 14
Al _x Ga _1-x As cathode graded layer (thickness: 20 nm, donor doping concentration N _D)
= 5 × 10 ¹⁷ cm ⁻³ , mixed crystal ratio x = 0.2 → 0.35) 1
46 and Al _0.35 Ga _0.65 As cathode layer (thickness 40n
m, donor doping concentration N _D = 5 × 10 ¹⁷ cm ⁻³ )
147 and Al _0.35 Ga _0.65 As cathode cathode ballast layer (thickness 150 nm, donor doping concentration N _D = 1 ×
10 ¹⁷ cm ⁻³ ) 148 and Al _x Ga _1-x As cathode ballast graded layer (thickness 50 nm, donor doping concentration N _D = 5 × 10 ¹⁷ cm ⁻³ , mixed crystal ratio x = 0.35)
→ 0.0) 149 and GaAs cathode cup layer (thickness 200 nm, donor doping concentration N _D = 5 × 10 ¹⁸
cm ⁻³ ) 1410 are laminated in the same pattern in this order. Reference numeral 1411 indicates an AuGe / Ni / Au anode ohmic electrode, 1412 indicates a Ti / Pt / Au base ohmic electrode, and 1413 indicates an AuGe / Ni / Au cathode ohmic electrode.

The arrow "→" in the above-mentioned doping concentration and mixed crystal ratio shows that the value changes from the bottom to the top in FIG. The doping concentration N _D of the donor in the GaAs active layer 144 is 1.4 × 10 ¹⁶ cm ⁻³ at the anode interface to 3 × 10 ¹⁶ c at the base interface.
It is noted that it has changed to m ^-3 . This HBTE
The measurement of D was performed, and the results of FIGS. 5 and 6 described above and FIG. 13 described below were obtained.

FIG. 13 shows the bias dependence of the maximum current gain of the grounded base HBTED. The input impedance and output impedance of this measurement are 50Ω.
In FIG. 13, the measured values of the current gain of the base-grounded HBTED are entered at several measurement points (represented by the symbol “◇”) set in the plane of the anode current vs. the anode-base voltage. ing. Here, the current gain is shown in FIG.
It exhibits a strong frequency dependence as shown in. The value entered at each measurement point in FIG. 13 is the highest current gain value obtained by changing the frequency. In the case of grounded base, the current gain due to normal transistor operation is 0 dB or less, so it can be said that the result of the high current gain shown in FIG. 13 is due to the transferred electron effect. The highest current gain occurs in the range 57 GHz to 60 GHz.
As indicated by the symbol “◯” in FIG. 13, HBTED may oscillate due to the transferred electron effect depending on the bias conditions. The oscillation due to the transferred electron effect has an oscillation frequency of 57 G.
Occurs in the range from Hz to 60 GHz. in this way,
The same HBTED operates in the amplifier / mixer mode and the oscillator / mixer mode depending on the bias conditions.

(Eighth Embodiment) FIG. 15 shows an embodiment in which a self-heterodyne down converter circuit 165 of a receiver is provided with a grounded cathode HBTED167. This self-heterodyne down conversion circuit 165 generally receives the signals (LO signal and RF signal) 162 transmitted by radio and receives the I signal in a frequency band lower than that of the RF signal.
The F signal 1610 is output. Cathode ground HBTED1
The bias condition of 67 is set so as to operate in the amplifier / mixer mode. As will be described in detail later, this embodiment is characterized in that the cathode of HBTED167 has a circular pattern shape.

Similar to the above-described first embodiment, for example, the transmission antenna 161 of the transmitter transmits the transmission signal 162 composed of the LO signal and the RF signal, and the reception antenna 1 of the receiver.
63. The LO signal and the RF signal are amplified by the low noise amplifier 164 and enter the self-heterodyne down converter circuit 165. Due to the influence of the input matching circuit 166, the power of the LO signal and the RF signal entering the cathode grounded HBTED 167 can be increased. This LO signal is amplified inside the grounded cathode HBTED 167 by the transferred electron effect. Furthermore, the cathode ground H
Inside the BTED167, this amplified LO signal and R
The F signal is mixed to generate an IF signal in a frequency band lower than that of the RF signal. The generated IF signal is amplified by the transistor operation of the grounded cathode HBTED167. Output circuit λ / 4 open stub 16
8 (the length is set to 1/4 with respect to the wavelength of the LO signal frequency), the LO in the HBTED active layer is affected.
The signal current is maximized, and the LO signal is not output from the self-heterodyne down-conversion circuit 165 so much. Further, due to the influence of the output IF matching circuit 169, the output IF
The power of the signal 1610 can be increased.

In this embodiment, the LO signal frequency is 5
At 9.01 GHz, the RF signal frequency is 59.4 GHz-
At 62.5 GHz, the IF signal frequency is 0.39 GHz-
3.49 GHz. Bandwidth of IF signal is 3.1GH
Since z is higher than the lowest frequency of 0.39 GHz of IF, it is important that the LO signal has a high amplification factor. In the present embodiment, as shown in FIG. 12, the power of the mixed LO signal (amplified inside the HBTED 17) 122 is larger than the power of the RF signal 121, so the power of the necessary IF signal 123 is in the IF band. The power of the unnecessary signal component 124 of 1 is greatly exceeded, and the unnecessary signal component 124 of the IF band does not become a problem.

The HBTED 167 is the HB shown in FIG.
It has the same layer structure as that of TED. HBTED
The active layer of 167 is GaAs, has a thickness of 1.7 μm, and is doped. The doping concentration of the active layer has a gradation from N _D = 1.0 × 10 ¹⁶ cm ⁻³ at the anode interface to N _D = 3 × 10 ¹⁶ cm ⁻³ at the base interface. The cathode of this HBTED167 has a circular pattern shape instead of a rectangular shape. Circular cathodes can be made smaller than known elongated rectangular cathodes. Therefore, the input impedance can be easily increased. The circular cathode is required to suppress the doping gradation (current spreading effect and stable transfer electron effect) of the active layer. If the area is small, the degree of doping gradation is high. Required) can be relatively low for a small area. Thereby, the transferred electron effect can be stably generated, and the HBTED can be easily operated in the amplifier / mixer mode or the oscillator / mixer mode. Thus, HBTE with a circular cathode
D is suitable as a component of a self-heterodyne converter circuit of a millimeter-wave band receiver.

The λ / 4 open stub 168 is designed so that the output circuit impedance is almost zero ohms with respect to the frequency of the LO signal. The input matching circuit 166 and the λ / 4 open stub 168 are made of ordinary microstrip lines or coplanar lines. The output IF matching circuit 169 is made of an MMIC capacitor and an inductor.

[0080]

As is apparent from the above, according to the self-heterodyne down converter circuit of the present invention, good characteristics can be exhibited with a simple circuit configuration. To provide a good self-heterodyne down-converter circuit.

Further, since the millimeter wave video transmission system of the present invention uses such a self-heterodyne down converter circuit in the receiver, the wide IF bandwidth, specifically, the maximum frequency is twice or more than the minimum frequency. Even a high IF bandwidth can withstand practical use. Moreover, since the conversion efficiency of the HBTED circuit is high, the power consumption of the receiver can be reduced.

Further, the HBTED of the present invention is suitable as a component of a self-heterodyne down converter circuit of a millimeter wave band receiver because the cathode has a circular pattern shape.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of a grounded cathode HBTED self-heterodyne receiver of the present invention.

FIG. 2 illustrates an embodiment of a grounded-base HBTED self-heterodyne receiver of the present invention.

FIG. 3 is a diagram showing an equivalent function of an oscillator / mixer mode HBTED included in a self-heterodyne down-converter circuit.

FIG. 4 is a diagram showing an equivalent function of an amplifier / mixer mode HBTED included in a self-heterodyne down-converter circuit.

FIG. 5: Single base ground HB in measured amplifier mode
It is a figure which shows the current gain-versus-frequency characteristic of TED.

FIG. 6: Measured amplifier mode single cathode ground H
It is a figure which shows the conversion loss versus frequency characteristic of BTED.

FIG. 7 illustrates an embodiment of the grounded cathode HBTED self-heterodyne receiver of the present invention.

FIG. 8 is a diagram showing an embodiment of a self-heterodyne receiver in which the grounded cathode HBTED and the IF amplifier of the present invention are integrally formed.

FIG. 9 is a diagram showing an embodiment of a self-heterodyne receiver in which the grounded cathode HBTED of the present invention and a low noise amplifier are integrally formed.

FIG. 10: 60 GH configured by incorporating the self-heterodyne down converter circuit of the present invention in a millimeter wave band receiver
It is a figure showing an embodiment of a millimeter wave image transmission system in a z-band home.

FIG. 11 is a diagram illustrating a problem that an unnecessary signal component is generated in the IF band when transmitting and receiving a signal with a wide bandwidth like a millimeter wave band communication system.

FIG. 12 shows a state in which an unnecessary signal component in the IF band is relatively small with respect to a required IF signal according to the present invention when a signal with a wide bandwidth is to be transmitted and received as in a millimeter wave band communication system. It is a figure.

FIG. 13 is a diagram showing the bias dependence of the maximum current gain of the grounded base HBTED, and showing that the same HBTED operates in the amplifier / mixer mode and the oscillator / mixer mode according to the bias conditions.

FIG. 14 is an HBTE used in each embodiment of the present invention.
It is a figure which shows the cross-section of D.

FIG. 15 illustrates an embodiment of a receiver using a self-heterodyne converter circuit with HBTED having a circular cathode according to one embodiment of the present invention.

[Explanation of symbols] [Explanation of symbols]

11, 21, 71, 81, 91 Transmit antenna 12, 22, 72, 82, 92 Transmitted LO signal and R
F signal 13,23,73,83,93 receiving antenna 14,24,74,84,94 low noise amplifier 15,25,75,85,95 self-heterodyne down converter circuit 16,26,76,86,96 input matching Circuit 17, 77, 87, 97 Cathode grounded HBTED 27 Base grounded HBTED 18, 28, 78, 88, 98 λ / 4 open stub 19, 29, 79, 89, 99 IF output matching circuit 110, 210, 710, 810, 910 IF output signal 711 λ / 8 transmission line 712 λ / 8 open stub 813 integrated IF amplifier 914 integrated low noise amplifier

Claims (16)

[Claims] 1. A self-heterodyne down-converter circuit provided in a receiver for receiving a radio frequency signal and a local oscillation signal, the signal being based on the received radio frequency signal and the received local oscillation signal. A self-heterodyne down-converter circuit comprising an HBTED for generating an intermediate frequency signal in a frequency band lower than the high frequency signal from the signal based on the above. 2. The self-heterodyne down converter circuit according to claim 1, wherein the signal based on the local oscillation signal is a signal obtained by internally amplifying the local oscillation signal by the HBTED by the transferred electron effect. Self-heterodyne down converter circuit. 3. The self-heterodyne down-converter circuit according to claim 1, wherein the signal based on the local oscillation signal is a signal generated by injection-locked oscillation by the HBTED internally by receiving the local oscillation signal. A self-heterodyne down-converter circuit characterized by being present. 4. The self-heterodyne down-converter circuit according to claim 1, wherein the HBTED is formed of a III-V group compound semiconductor, and In, Ga, and Al are added as the group III element. A self-heterodyne down converter circuit comprising at least one of As, P, N, and Sb as the V group element. 5. The self-heterodyne down-converter circuit according to claim 1, wherein the HBTED is formed on a semi-insulating GaAs substrate. 6. The self-heterodyne down converter circuit according to claim 1, wherein the HBTED is grounded to the base. 7. The self-heterodyne down converter circuit according to claim 1, wherein the HBTED is grounded at the cathode. 8. The self-heterodyne down converter circuit according to claim 1, wherein the signal power input to the HBTED is high in the frequency band of the local oscillation signal. A self-heterodyne down converter circuit characterized in that a passive circuit (16, 26, 76, 86, 96) is connected to an input terminal. 9. The self-heterodyne down-converter circuit according to claim 1, wherein the anode of the HBTED is arranged so that the signal power output by the HBTED becomes high in the frequency band of the intermediate frequency signal. Passive circuit (19, 29, 79, 89, 9)
9) is connected to the self-heterodyne down converter circuit. 10. The self-heterodyne downconverter circuit according to claim 1, wherein the output impedance of the HBTED is substantially zero in the frequency band of the local oscillation signal.
Passive circuit (18, 28, 711,
712, 88, 98) are connected to the self-heterodyne down converter circuit. 11. The self-heterodyne downconverter circuit according to claim 1, wherein the output impedance of the HBTED is substantially zero in the frequency band of the local oscillation signal, and the HBTE.
As the output impedance of D is substantially infinite in the frequency band of the second harmonic of the local oscillation signal, the HBTE
A self-heterodyne down converter circuit in which a passive circuit (711, 712) is connected to the anode terminal of D. 12. The self-heterodyne down-converter circuit according to claim 1, wherein the HBTED and the passive circuit are integrally formed on a semiconductor substrate. circuit. 13. The self-heterodyne downconverter circuit according to claim 1, wherein the HBTED and an IF signal amplifier for amplifying an intermediate frequency signal generated by the HBTED are the same semiconductor. A self-heterodyne down converter circuit, wherein the IF signal amplifier is integrally formed on a substrate, and the IF signal amplifier is composed of at least one transistor having the same layer structure as that of the HBTED. 14. The self-heterodyne down-converter circuit according to claim 1, wherein the HBTED and a low noise amplifier (LNA) for amplifying a signal input to the HBTED, A self-heterodyne down converter circuit, wherein the low noise amplifier is integrally formed on the same semiconductor substrate, and the low noise amplifier is composed of at least one transistor having the same layer structure as that of the HBTED. 15. A millimeter wave video transmission system using the self-heterodyne down-converter circuit according to claim 1 for a receiver. 16. A semi-insulating substrate, at least an anode layer, an active layer, a base layer, a cathode graded layer, a cathode layer, a cathode ballast layer, a cathode ballast graded layer, and a cathode cup layer. In the HBTED having the following items, the cathode graded layer, the cathode layer, the cathode ballast layer, the cathode ballast graded layer, and the cathode cup layer have a circular pattern shape having an area smaller than that of the base layer. Self-heterodyne down converter circuit.