KR20040027639A - Harmonic Mixer using NRD guide - Google Patents

Abstract

PURPOSE: A harmonic mixer by using a non radiative dielectric(NRD) waveguide is provided to obtain a stable oscillation output by reflecting the difference signal on the phase locked loop circuit. CONSTITUTION: A harmonic mixer by using a non radiative dielectric(NRD) waveguide includes a top substrate, a bottom substrate(1b), a diode mount(3) a Schottky diode(2), a rear teflon block and a subminiature(SMA) connector(7). The NRD linear and curved waveguides are arranged on the diode mount(3) attached thereto the Schottky diode(2) between the top substrate and the bottom substrate(1b). The high dielectric index sheet is attached between the Schottky barrier diode mount and the NRD waveguide for matching the impedance. The harmonic pattern is etched on the substrate to generate a high order frequency by inserting the metal thin film pattern and the LO signal as a reference oscillation frequency to receive the RF signal. The rear teflon block is attached to the rear side of the Schottky barrier diode mount. And, the subminiature(SMA) connector(7) and the external circuits are installed on the rear side of the bottom substrate(1b).

Description

Harmonic Mixer using NRD Guide

Recently, the millimeter wave band has been researched for the private sector application with the expansion of the wireless communication market. In particular, the 60-GHz V-band (50-75 GHz) is emerging as a frequency for indoor and short-range wireless communication for high-speed broadband communications. Mixer, one of the important components for miniaturization and low cost of such millimeter wave high-speed wireless system, requires the development of a millimeter wave oscillator with good characteristics for the LO input which is essential for operation.

However, the development of an oscillator with good output characteristics in the millimeter wave band is not only very difficult but also expensive, increasing the cost of the overall system. For this reason, MMIC harmonic mixers have been proposed as an alternative to conventional mixers.

The MMIC harmonic mixer uses relatively low frequency because it uses 1 / n of the LO frequency used in the conventional mixer, and has the advantage of excellent LO signal-to-RF signal isolation. Because of its loss characteristics, additional signal amplification is required. In addition, the manufacturing process itself is not easy, there is a disadvantage that the process cost is high.

Also, in the phase-locked loop method of the oscillator using the NRD guide, the harmonic mixer is an essential device for inducing the mixing of the reference frequency LO signal and the changed frequency RF signal to obtain the IF frequency signal through the difference frequency component. .

In order to solve the above problems in the present invention, the following harmonic mixer was constructed. A harmonic mixer, comprising: an NRD guide line for transmitting an RF signal, a high dielectric constant sheet for impedance matching, a schottky diode mount, a rear Teflon block, a bias line, and an SMA connector for receiving an LO signal; The diode mount that outputs the IF signal consists of a Schottky barrier diode and a metal thin film pattern capable of receiving RF signals, and a harmonic pattern that generates harmonic frequencies by inserting a LO signal, which is a reference oscillation frequency, on the substrate. Therefore, the desired frequency source is changed by the external environment ) And the nth harmonic signal of the reference frequency source LO signal ( IF signal by mixing So that the frequency difference component ( ) Is applied to the VCO to induce the phase fixation of the oscillator. This millimeter wave harmonic mixer was constructed using NRD guide, which is known to have no conversion loss.

1 is a perspective view showing a harmonic mixer applied to the phase locked loop of the oscillator

2 is a perspective view showing the termination of the harmonic mixer

3: Front view showing the termination of the harmonic mixer

Figure 4: External circuit behind the bottom conductor plate installed for IF output

5 is a conceptual diagram illustrating the operation principle of the harmonic mixer

Fig. 6: Graph showing conversion loss for IF signal

7 is a graph showing the isolation characteristics of the harmonic mixer

<Description of the symbols for the main parts of the drawings>

1a: upper conductor plate

1b: lower conductor plate

2: Schottky Diode

3: Schottky Diode Mount

4: metal thin film for RF reception

5: bias line

6: semi-rigid cable

7: SMA connector (for LO transmission)

8: Dielectric Resonator Oscillator (DRO)

9: NRD guide curve

10: Terminator

11: gun diode mount

12: Metal thin film choke with 1/4 wavelength step structure

13: strip resonator

14: LSE Mode Press

15: NRD guide straight line

16: High dielectric constant sheet for impedance matching

17: rear teflon block

18: Microstrip line with impedance 50Ω

19: 1 / 4-wavelength 5-step choke for LO leakage prevention

20: Structure of 1 / 2-wavelength stub line

21: thin film of IF output side

22: LO thin film on the input side

1 of the present invention is a perspective view showing the application of the harmonic mixer to the phase-locked loop method of the oscillator in the method of configuring a harmonic mixer using the NRD guide. In Fig. 1, the frequency source of the oscillation circuit uses a millimeter wave gun diode, a diode mount 11 in which the gun diode is fixed, a choke 12 having a quarter wavelength three-step structure, A strip resonator 13, an LSE mode press 14 and an NRD guide straight line 15; Obtain a 1/2 RF split frequency signal through a 3dB directional coupler 9; This RF signal is transmitted to the harmonic mixer (original).

In FIG. 1, the operating frequency of the NRD guide dry oscillator is 60 GHz, and the frequency of the VCO which emits a specific frequency according to the input voltage is changed by the influence of temperature and ambient electromagnetic environment, and the changed frequency is a 3 dB directional coupler. Is reflected when the signal is distributed. The power distributed in the 3dB directional coupler is divided by 1/2 of the original 60 GHz signal power. Was made.

In the present invention, Figure 2 is a perspective view showing the end of the harmonic mixer. As shown in FIG. 2, the harmonic mixer is composed of an NRD guide line 9, a high dielectric constant sheet 16, a Schottky barrier diode mount 3, and a rear Teflon block 17. As shown in FIG.

In the schottky barrier diode mount, the diode mount for outputting the IF signal includes a schottky barrier diode and a metal thin film pattern capable of receiving an RF signal, and a harmonic pattern generating a harmonic frequency by inserting a LO signal which is a reference oscillation frequency. It is comprised in the form which etched into the board | substrate.

In the present invention, Figure 3 shows a front end view of the harmonic mixer. As shown in FIG. 3, the harmonic mixer has a Schottky barrier diode mount 3, a ground line 5, a bias line 5, and an IF sending terminal semig-rigid-cable 6 on the lower conductor plate 1b. ) And the LO signal receiving terminal.

The metal electrode and the harmonic pattern structure of the diode mount has a metal plate-type metal thin film electrode having a width of 1.4 mm and a length of 2.5 mm equal to the width of the line, and a GaAs short in the 0.4 mm gap provided at the center. A schottky barrier diode 2 was mounted using a conductive epoxy. In addition, the millimeter wave (RF) installed on both sides of the electrode is a 1 / 4-wavelength step choke (4) to prevent leakage. It is provided with 2 stages on the ground side and 6 stages on the LO side. A two-wavelength stub 20 is provided, and the gap on the LO input side is half wavelength of the LO so that it is equivalently shorted and opened to the sixth order IF. The diode mount was integrated by etching on a Teflon substrate having a relative dielectric constant of 2.6 and a thickness of 0.265 mm.

In the present invention, Fig. 4 is a structure shown by providing a stub 20 of LO in a line in the diode mount configuration, where 21 is an IF output side pattern and 22 is an LO input side pattern. Also, various types of transmission line stubs have been shown in FIGS. 4A to 4F. As shown in Fig. 4, (a) is a straight line, and (b) both sides of the core of the connector are enlarged by about 1/4 wavelength of the LO signal. (c) is the contact surface of the connector part is wide, and (d) is 0.225mm gap on both sides of the connector to increase the size by 1/4 wavelength of LO. (d ') makes the gap of (d) 0.1 mm. (e) is the sum of (c) and (d), and (e ') is the sum of (c) and (d'). (f) is the sum of (b) and (c).

In the present invention, Figure 5 shows the external circuit behind the lower conductor plate (1b) provided for the IF output of the diode mount sixth order. As shown in Fig. 5, the external circuit is a microstrip line 18 having a characteristic impedance of 50 ohms having a relative dielectric constant of 2.6, a thickness of 0.365 mm, and a strip width of 1 mm, and has five stages in a 1/4 wavelength choke to prevent leakage of LO. It is installed. In addition, the low-pass filter separates the sixth order IF and direct current components.

In the harmonic mixer, FIG. 6 is a conceptual diagram illustrating the operation principle. The LO signal transmitted to the dielectric resonance oscillator (DRO) is a harmonic signal of primary, secondary and tertiary components ( , , It is a local oscillation signal with 10GHz band. The VCO signal is an RF signal (half of the signal power changed as the dry oscillation signal of FIG. 1 is transmitted). )to be. The RF signal, which is a distribution signal, is mixed in the harmonic mixer to be compared with a reference frequency in the 10 GHz band. In particular, the third harmonic signal among harmonic signals is three times the reference frequency signal. IF signal compared with ) Is generated. After filtering out unnecessary harmonics of IF signal through low pass filter, The signal came out, and this signal reflected the final output signal from the phase locked loop circuit to the input voltage of the VCO of the oscillator.

In the present invention, Figure 7 shows the conversion loss according to the IF frequency band when the IF output using the harmonic mixer. As a result, it can be seen that a constant conversion loss of less than 8dB up to 1GHz. At this time, if the bias current is 5.7mA, the local oscillation frequency is 10GHz and the RF frequency is 30GHz, the conversion loss is about 8dB or less.

In the present invention, Figure 8 is a graph showing the isolation characteristics of the harmonic mixer. In FIG. 7, the LO-to-RF isolation characteristic is -23dB at 10 GHz, which is the LO frequency, and the LO-to-IF isolation characteristic is -35dB. Therefore, it can be seen that it shows superior LO to RF isolation characteristics compared to the conventional mixer.

In the present invention, a harmonic mixer was constructed using the NRD guide. In particular, the IF signal, which is the difference between the two signals, is obtained by combining the RF signal incident on the Schottky barrier diode mount and the LO signal with the third harmonic component, and reflected in the phase-locked loop circuit of the oscillator by the difference signal. Thus, more stable oscillation output characteristics could be obtained.

In addition, the embodiment was carried out in the 60 GHz band, and because of the characteristic of the harmonic mixer, it is possible to mix the RF signal and the LO signal using harmonic components in other millimeter wave bands.

Therefore, the harmonic mixer using the NRD guide implemented by the present invention may replace the existing MMIC harmonic mixer.

Claims (8)

In the method of configuring a harmonic mixer using an NRD guide, NRD guide straight lines and curved lines are arranged in the diode mount with Schottky barrier diode attached between the upper and lower conductor plates; An impedance matching high dielectric constant sheet is attached between the Schottky barrier diode mount and the NRD guide line; The diode mount for outputting the IF signal comprises a Schottky barrier diode and a metal thin film pattern capable of receiving an RF signal, and a harmonic pattern for generating harmonic frequencies by inserting a LO signal, which is a reference oscillation frequency, on the substrate; A rear teflon block is attached to the rear of the Schottky barrier diode mount; Behind the lower conductor plate there is an external circuit and SMA connector for the IF output; Harmonic mixer using NRD guide, which is composed of SMA connector for transmitting LO signal The method of claim 1, The Schottky barrier diode mount 3 mounted on the lower conductor plate 1b includes a metal thin film electrode for RF signal input, an harmonic pattern on the input side of the LO signal as the basic oscillation frequency, an IF output metal thin film pattern, a ground line, a bias line, and the like. Harmonic mixer using IF output terminal semig-rigid -cable and NRD guide The method according to claim 1 and 2, The structure of the diode mount is a metal plate-like electrode and a GaAs Schottky barrier diode (2) mounted on the center gap (gap) using a conductive epoxy; 1 / 4-wavelength step chokes for preventing leakage of millimeter waves (RF) provided on both sides of the electrode are provided in two stages on the ground side and six stages on the LO side; Install a half-wave stub of LO on the track; The gap on the LO input side is half the wavelength of the LO so that it is equivalently shorted; The six stages of IF were configured to be open; Harmonic mixer using NRD guide, the diode mount is integrated on the Teflon substrate by etching The method of claim 3, In the installation of the diode-mounted stub 20 on the line, 21 is an IF output side pattern, 22 is an LO input side pattern, and a is a straight line; (b) increased both ends of the connector's core wire by a quarter wavelength of the LO signal; (c) is the contact surface of the connector portion is wide; (d) is 0.225mm wide on both sides of the connector to increase the size by 1/4 wavelength of LO; (d ') is 0.1 mm of gap; (e) is the sum of (c) and (d) and (e ') is the sum of (c) and (d'); (f) is a harmonic mixer using an NRD guide characterized by the combination of (b) and (c). The method of claim 1, The structure of the external circuit behind the lower conductor plate provided for the IF output of the diode mount six stages is a microstrip line 18 having a characteristic impedance of 50Ω with a strip width of 1 mm; 5 stages are installed in 1/4 wavelength choke to prevent LO leakage; Low-pass filter is harmonic mixer using NRD guide, which is configured to separate IF and DC components of 6 stages The method of claim 1, The LO signal source is a harmonic mixer using an NRD guide, using a dielectric resonance oscillation element and an NRD guide oscillation element. NRD guide RF signals transmitted on straight and curved lines Is incident on the Schottky barrier diode mount, and the LO signal, Nth harmonic, Is mixed with the signal incident from the diode mount Harmonic Mixer Using NRD Guide Featuring IF Signal of The method of claim 3, The Nth harmonic signal generated through the harmonic mixer RF frequency and Harmonic mixer using NRD guide, characterized in that configured to have a relationship