KR100531136B1 - A 6-port for a direct conversion receiver - Google Patents

Abstract

Four micro strips for connecting alternately to two dielectric layers in parallel; Non-coupling lines formed between ends of two coupling lines to connect two coupling lines of the coupling lines; Two input terminals for receiving an RF signal and a local oscillation signal, respectively; 6 port for a direct conversion receiver comprising four output terminals appearing with the phase difference of 0 °, 90 °, 180 ° and 270 ° the same size as the two signals input through the two input terminal.

Description

6-port for a direct conversion receiver

The present invention relates to a six-port (6-port) of the front end used in a direct conversion method in a wireless communication transceiver, and more specifically, four micro directional couplers without using a ring hybrid or quadrature hybrid. The present invention relates to a six-port for a direct conversion receiver that can perform the same function by combining.

The most common type of receiver in modern communication devices is a superheterodyne receiver. This receiver can be found in television sets, telephones and radios in a home, office or car.

Superheterodyne receivers are widely used, but they use an image rejection filter and an intermediate frequency (IF). As a result, superheterodyne receivers are not ideal for application in small and low cost mobile communication systems such as cellular telephones, pagers, cordless telephones and the like.

As the demand for small size, light weight, low price, low power consumption, etc. of wireless transmitter and receiver increases, many researches on new wireless system structure and RF components have been conducted. The most representative of these is to convert the structure of the RF stage from the existing superheterodyne method to homodyne, that is, a direct conversion method.

Direct conversion receivers offer significant advantages over superheterodyne receivers. The direct conversion receiver directly converts the input signal into its baseband signal, thereby eliminating the step of initially converting the RF signal into an IF signal. Therefore, all intermediate filters, mixers and amplifiers can be omitted, which simplifies the circuit. Next, except for the preselector filter, the direct conversion receiver uses only a low pass filter rather than a band pass filter. Typically, it is easier to integrate a lowpass filter on one chip than a bandpass filter. Therefore, a direct conversion receiver can be constructed on one integrated circuit, which is usually smaller and cheaper than a superheterodyne receiver.

1 is a structure of a 6-port direct conversion receiver front-end, which includes a duplexer 101, a low noise amplifier 102, a 6 port 103, a detection circuit 104, and a low pass filter. It consists of 105. Reference numeral 106 is a transmission port, 107 is a local oscillator input port, 108 is an I channel output port, 109 is a Q channel output port. The concept of a six-port is described here by Cohn and Weinhouse in 1964, "An automatic microwave phase measurement system," Microwave Journal, vol. 7, no. 2, pp. 49-56.

The 6 port is a circuit with two inputs and four outputs and the output port is terminated with a power detection circuit. Knowing the electrical relationship between the input and output ports reveals the correlation between the two input signals (phase, amplitude), where the six ports are linear and the output signals should not be linearly dependent on each other. Therefore, six ports have been used mainly in network analyzers, and Hoer and Roe interpreted the structure in 1975, "Using an arbitrary six-port junction to measure complex voltage ratios," IEEE Trans. Microwave Theory and Techiques., Vol. MTT-23, pp. Published in 978-984.

6 ports have been applied with the direct conversion method, and the structure is shown in FIGS. 2 and 3, respectively.

2 is composed of four patterns, namely, two ring hybrids 201, a quadrature hybrid 202, and a power divider 203. In the drawing, the portion indicated by the comb pattern is the conductor portion of each pattern embodied on the dielectric, and the solid line is the conductive line connecting the patterns. RF signals and local oscillator signals are applied to ports 204 and 205 or 206, respectively, and the signals are output to output ports 207, 208, 209, and 210 through respective paths. At this time, the phase difference of the signals output from the four output ports is 0 degrees 90 degrees 180 degrees 270 degrees so that the DC voltage can be detected by the detection circuit next to the six ports. Compared with the structure shown in FIG. 3, the six ports shown in FIG. 2 have a disadvantage in that the connecting ports cross each other.

The operation characteristics of the six ports having the structure shown in FIG. 3 are the same as those of FIG. 2 and consist of three quadrature hybrids 301 and one power divider 302.

The 6-port structure used in FIGS. 2 and 3 is limited in implementation at low frequencies due to the size of the ring hybrid and quadrature hybrid. In particular, it is difficult to implement an integrated circuit at 3 GHz to 10 GHz. In addition, the two input and output ports are staggered, which reduces flexibility in connecting to external circuits.

The present invention provides a six-port structure with a new structure that operates like a conventional six-port without using a power divider, a ring hybrid, and a quadrature hybrid.

It is another object of the present invention to provide a structure that is smaller in size than a ring hybrid or quadrature hybrid, which is advantageous in miniaturizing a product and implementing it in an integrated circuit.

Still another object of the present invention is to freely connect an external circuit by placing an input port and an output port in an arbitrary position.

Hereinafter, with reference to the accompanying drawings will be described the configuration of the six port and its operation according to the present invention.

Power dividers, ring hybrids, and quadrature hybrids used in conventional six ports can be replaced by directional couplers. 4 is an exploded perspective view showing the structure of the directional coupler, wherein the metal patterns are located on two dielectric layers in parallel. The comb portions 405 and 406 are metallic patterns and the dotted portions 407 are dielectric.

As a principle of operation, when a signal is applied to the input port 401, a signal having the same size and 90 degree difference in phases from the ports 402 and 403 is output and no signal is output to the port 404. In 2000 by IEEE Microwave and Guided Wave Letters, vol. 10, no. 2, pp. 58-60. The directional coupler has the same electrical characteristics as a ring hybrid or quadrature hybrid in a specific frequency range, and its area can theoretically be reduced from one-sixteenth to one-half to an integrated circuit.

5 is a perspective view showing the configuration of a six port according to the present invention constructed using the principle of the directional coupler. The metal patterns 501 to 508 are formed on the two dielectric layers 51 and 52 and stacked together with the remaining dielectric layers 53.

The lower dielectric layer 51 is made as shown in FIG. It consists of a plurality of coupling lines (501, 503, 505, 507) and the non-coupling line (b) connecting the end portions 501a and 505a, 503a and 507a of each coupling line, respectively.

FIG. 7 illustrates the intermediate dielectric layer 52 of FIG. 5, and has a structure similar to that of FIG. 6, with a plurality of coupling lines 502, 504, 506, and 508 and terminations 502a and 508a, 504a, and 506a of each coupling line. ) Is composed of a non-coupling line (b) connecting each.

FIG. 8 is a planar projection view of a structure drawn by overlapping the metal patterns of FIGS. 6 and 7. Ports 501, 502, 503, and 504 apply signals to 501 and 503 or 502 and 504 as input ports for RF signals and local oscillator signals, and the other ports are match terminated. Ports 505, 506, 507, and 508 are output ports, and the phase differences of the signals received from the two input ports are 0 degrees, 90 degrees, 180 degrees, and 270 degrees, respectively.

The uncoupling line (b) has a correlation of 509 and 510 where the electrical length of 509 is an odd multiple of 90 ° compared to the electrical length of 510.

The electrical length is described as follows. Assuming that there is a transmission line of 5M, the wavelength becomes 0.5 wavelength (λ) when viewed at a frequency of 30 MHz, and 5λ length on the 300 MHz frequency reference.

Because of,

The wavelength at 30 MHz is to be. That is, since 10m physical transmission line is required to satisfy 1λ at 30MHz, the transmission line of 5m becomes relatively 0.5λ,

The wavelength at 300MHz to be. That is, since 1m physical transmission line is required to satisfy 1λ at 300MHz, the 5m transmission line becomes 5λ relatively.

In other words, since the physical length is different from the electric length in terms of the frequency used, the new definition of the length that is the same length regardless of the frequency is called electrical length. That is, the length of one wavelength (for each frequency) is 2π in electrical length, and the unit is radians. It is also expressed in degrees (°).

… … (One)

Ⅰ) When the electrical length of 30MHz is 90 °, the physical length is obtained by applying the above formula (1).

Thus, physical length Becomes

Ii) when the electrical length of 300 MHz is 90 °,

In other words, the electrical length of 90 ° means that it is ¼ wavelength and the physical length varies with frequency. If the electrical length of the 510 is 60 °, the electrical length of the 509 is different by an odd multiple of 510 and 90 °.

60 ° + 90 ° = 150 °, i.e. 60 ° + 1 × 90 °,

60 ° + 270 ° = 330 °, that is, 60 ° + 3 × 90 °,

60 ° + 450 ° = 510 °, that is, 60 ° + 5 × 90 ° and so on.

9 is a perspective view of a six port according to another embodiment of the present invention, Figure 10 is a perspective view of FIG.

The structure in the case where the input port direction 503 and 504 of FIG. The connecting leads 601 and 602, 603 and 604 intersect with each other, but the different layers are located, so it is not a problem at all.

As described above, in the present invention, a three-layer directional coupler is applied to six ports, thereby reducing the overall size and changing the direction of the input / output port, thereby making the connection characteristic with the external circuit flexible. Therefore, it is advantageous to manufacture the direct conversion receiver front end into a single chip, and the manufacturing cost can be reduced.

1 is a structural diagram of a direct conversion receiver front end;

Figure 2 is a structure of a conventional six port one embodiment,

3 is another embodiment of the conventional six-port structure diagram;

4 is a structural diagram of a directional coupler;

5 is a perspective view showing the configuration of a six-port according to the present invention,

6 is a structural diagram of a lower layer metal pattern in the six-port structure of FIG.

7 is a structural diagram of the upper layer metal pattern in the six-port structure of FIG.

FIG. 8 is a combined projection view of FIGS. 6 and 7;

9 is a perspective view of a six-port according to another embodiment of the present invention,

10 is a combined projection of FIG. 9.

Claims (5)

Two input terminals for receiving the RF signal and the local oscillation signal, respectively, and output terminals having the same magnitude as those of the two signals input through the two input terminals with phase differences of 0 °, 90 °, 180 °, and 270 °. 6 port for a direct conversion receiver having; A first dielectric layer having two pairs of metal pattern coupling lines connected to each other by an uncoupling line, and two pairs formed at positions mutually opposite to each coupling line formed in the first dielectric layer to induce the occurrence of multiple coupling; And a directional coupler in which a second dielectric layer on which a metal pattern coupling line is disposed is stacked in parallel with each other above and below. delete Four micro strips for connecting alternately to two dielectric layers in parallel; Uncoupling lines formed between ends of two coupling lines to connect two coupling lines of the coupling lines; Two input terminals for receiving an RF signal and a local oscillation signal, respectively; 6 port for a direct conversion receiver comprising four output terminals appearing with the phase difference of 0 °, 90 °, 180 ° and 270 ° the output signal of the same size as the two signals input through the two input terminal. The 6 port for a direct conversion receiver according to any one of claims 1 to 3, wherein the output terminals are formed in the same direction. The 6 port for a direct conversion receiver according to claim 4, wherein the input terminals are formed in the same direction as the direction in which the output terminals are formed.