CN103457555A - Millimeter wave amplifier unilateralization network using on-chip transformer with random coupling coefficient - Google Patents

Abstract

The invention discloses a millimeter wave amplifier unilateralization network using an on-chip transformer with a random coupling coefficient. The network comprises a common source structure amplifier (1) and the on-chip spiral transformer (2). A primary coil (21) and a secondary coil (22) of the transformer (2) are respectively connected to a grid electrode and a drain electrode of the common source structure amplifier (1), voltage-current feedback is introduced, specific unilateralization conditions are met by regulating a self-inductance value of the secondary coil and a grid-drain stray capacitance of a transistor is offset by resonance, so that reverse isolation of the common source amplifier is greatly improved and the defects of high requirement on the coupling coefficient of the transformer and poor reverse isolation of a conventional millimeter wave common source amplifier are overcome.

Description

Use has the millimeter wave amplifier unilateralization network of the on-chip transformer of arbitrarily coupling coefficient

Technical field

The present invention relates to a kind of millimeter wave amplifier unilateralization network, is that a kind of semiconductor integrated circuit technique that adopts makes, uses the on-chip spiral transformer to improve the circuit network structure of millimeter wave common-source amplifier reverse isolation degree specifically.

Background technology

The electric capacity of the parasitism between the parasitic capacitance of transistor inside, especially grid and drain electrode, can introduce parasitic reverse signal coupling path at tube interior, and the feedback network of this inside brings adverse influence usually can to the design of millimeter wave amplifier.For example, in design during a multistage common-source amplifier, while regulating the output matching network of every one-level amplifier, the input impedance meeting is affected, and needs the redesign input matching network; After designing input matching network, transistorized output impedance can change again, needs again to redesign conversely output matching network, thereby affects the design of whole amplifier.In order to solve the bad problem of millimeter wave amplifier isolation, usually need to use the amplifier of cascodes, the transistor that is about to the transistor of a common source configuration and the common gate structure use that gathers into folds.But than common source configuration, cascodes needs the drain voltage of twice, is unfavorable for being applied in the low supply voltage environment.In addition, the common gate structure transistor in cascodes usually can be introduced extra noise, affects the noiseproof feature of whole amplifier.

Another method that improves amplifier reverse isolation degree is by increasing extra circuit network transistor is peripheral, resonance or balance out the parasitic capacitance of tube interior, thus improve the reverse isolation degree.This method usually is called as amplifier unilateralization technology.Traditional unilateralization technology mainly is included on common-source amplifier and adds extra on-chip inductor and on-chip transformer etc.After between transistor gate and drain electrode, connecting extra inductance, can between inductance and transistor gate-drain capacitance, form shunt-resonant circuit, offset the impact of parasitic capacitance, improve reverse isolation.But this method usually needs the stray inductance of using the sense value very large, need to take larger chip area.After using the unilateralization technology of on-chip transformer, the area of comparing the inductance domain can be effectively reduced.Traditional transformer unilateralization technology is the primary and secondary coil that adds transformer between transistorized drain electrode and source electrode, needs to use coupling coefficient to approach 1 close coupling transformer.Yet at millimeter wave frequency band, realize that coupling coefficient approaches 1 close coupling on-chip transformer more difficult, because usually can in transformer, introduce more multiparasitization electric capacity when increasing the primary and secondary coil coupling of transformer, thereby reduce the self-resonant frequency of transformer.

Therefore, need invention a kind ofly can use on-chip transformer with arbitrarily coupling coefficient, be applied to the millimeter wave amplifier unilateralization circuit network in low supply voltage common-source amplifier structure simultaneously.

Summary of the invention

Goal of the invention: the objective of the invention is to design and a kind ofly can use on-chip transformer with arbitrarily coupling coefficient, be applied to the millimeter wave amplifier unilateralization circuit network in low supply voltage common-source amplifier structure simultaneously.

The present invention adopts following technical scheme:

A kind of millimeter wave amplifier unilateralization network that uses on-chip transformer, it comprises common source structure amplifier, on-chip spiral transformer.The on-chip spiral transformer is connected between the grid and drain electrode of common source structure amplifier.Wherein, the secondary coil induced voltage of transformer, then feeds back on grid with the form of electric current by transformer coupled in primary coil, forms the degenerative structure of voltage-to-current.Suppose that transformer is primary and secondary

$L_{\mathrm{sc}}=\frac{n}{C_{\mathrm{gd}}\&CenterDot;{\mathrm{\&omega;}}^2}\&CenterDot;\frac{{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="130912144445.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}{1-{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="130912144445.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}$

The turn ratio of coil is n, and the coupling coefficient of transformer is k, and transistorized grid leak parasitic capacitance value is C _gd, the self-inductance value of secondary coil is L _sc, the angular frequency that ω is the amplifier working frequency range, when these parameters meet following relational expression:

Can make common-source amplifier meet the unilateralization condition in this frequency range, the grid leak parasitic capacitance of resonance offseting transistor, significantly improve transistorized reverse isolation degree.From above-mentioned formula, can find out, this unilateralization network has no particular limits the coupling coefficient of on-chip transformer, can use coupling coefficient arbitrarily, is suitable for use on millimeter wave frequency band.If need to change the working frequency range of amplifier, only need to change the self-inductance value of transformer secondary output coil or the turn ratio of primary and secondary coil.

The present invention has the following advantages:

1) significantly improve the reverse isolation degree of millimeter wave common-source amplifier.

2) on-chip transformer is not had to special requirement, can select the on-chip spiral transformer of arbitrarily coupling coefficient.

3) be suitable for the application scenario of low supply voltage millimeter wave amplifier.

The accompanying drawing explanation

Fig. 1 is the basic structure schematic diagram that uses the millimeter wave amplifier unilateralization network of arbitrarily coupling coefficient on-chip transformer in the present invention;

Fig. 2 is applied in the circuit theory diagrams in Q-band millimeter wave common-source amplifier by the present invention;

Fig. 3 is applied in an on-chip transformer structural representation in Q-band millimeter wave common-source amplifier by the present invention;

Fig. 4 is applied in the present invention the reverse isolation degree test result of amplifier after a Q-band millimeter wave common-source amplifier;

Fig. 5 is applied in the present invention gain, the input and output standing wave S parameter testing result of amplifier after a Q-band millimeter wave common-source amplifier.

Embodiment

Below in conjunction with accompanying drawing, the present invention is done further and explains.

As shown in Figure 1, basic structure of the present invention is a kind of millimeter wave amplifier unilateralization network that uses on-chip transformer, and it comprises common source structure amplifier 1, on-chip spiral transformer 2.On-chip spiral transformer 2 is connected between the grid and drain electrode of common source structure amplifier 1.Wherein, the secondary coil 22 induced drain voltages of transformer, then feed back on grid with the form of electric current by transformer coupled in primary coil 21, form the degenerative structure of voltage-to-current.

Fig. 2 is applied in the circuit theory diagrams in Q-band millimeter wave common-source amplifier by the present invention.As shown in the figure, this amplifier first order 3 adopts the degenerative structure of source electrode perception; The unilateralization network of the use arbitrarily coupling coefficient transformer that the second level 4 and the third level 5 adopt the present invention to propose.In figure, drain power voltage is 1.2V, and gate bias voltage is 0.7V.

Fig. 3 is applied in an on-chip transformer structural representation in Q-band millimeter wave common-source amplifier by the present invention.Wherein an end 6 of the primary coil of transformer connects transistorized gate bias voltage, and the other end 8 of primary coil connects transistorized grid.One end 7 of the secondary coil of transformer connects transistorized drain power voltage, and the other end 9 of secondary coil connects transistorized drain electrode

Fig. 4 is applied in a reverse isolation degree test result after Q-band millimeter wave common-source amplifier by the present invention.As can be seen from the figure, when not using the unilateralization network, the reverse isolation degree is in 26dB, after the unilateralization network that uses the present invention to propose, more than the reverse isolation degree can be improved to 40dB.

Fig. 5 is applied in gain, an input and output standing wave S parameter testing result after Q-band millimeter wave common-source amplifier by the present invention.As can be seen from the figure, the maximum gain that this amplifier reaches when frequency is 46GHz (S21 result) is 18.3dB, the input standing wave (S11 result)-below 5dB, output standing wave (S22 result)-below 10dB.

The present invention and the Q-band millimeter wave common-source amplifier be applied in thereof all adopt silica-based complementary mos integrated circuit technique to realize.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (4)

1. a use has the millimeter wave amplifier unilateralization network of the on-chip transformer of arbitrarily coupling coefficient, it is characterized in that, described millimeter wave amplifier unilateralization network comprises common source structure amplifier (1), on-chip spiral transformer (2), and described on-chip spiral transformer (2) comprises primary coil (21) and secondary coil (22); The primary coil of on-chip spiral transformer (2) (21) and secondary coil (22) are connected on the grid and drain electrode of common source structure amplifier (1), described secondary coil (22) induced drain voltage, by described on-chip spiral transformer (2), be coupled in primary coil (21), form with electric current feeds back on grid again, form the degenerative structure of voltage-to-current, meet specific unilateralization condition by the self-inductance value of regulating described secondary coil (22), wherein, described on-chip spiral transformer (2) can use coupling coefficient arbitrarily.

2. millimeter wave amplifier unilateralization network according to claim 1, is characterized in that described list

$L_{\mathrm{sc}}=\frac{n}{C_{\mathrm{gd}}\&CenterDot;{\mathrm{\&omega;}}^2}\&CenterDot;\frac{k^2}{1-k^2},$

To the change condition, be:

Wherein, L _scfor the self-inductance value of secondary coil, the turn ratio that n is the primary and secondary coil of transformer, the coupling coefficient that k is transformer, C _gdfor transistorized grid leak parasitic capacitance value, the angular frequency that ω is the amplifier working frequency range.

3. millimeter wave amplifier unilateralization network according to claim 1, it is characterized in that, if need to change the working frequency range of described common source structure amplifier (1), only need to change the self-inductance value of secondary coil (22) of described on-chip spiral transformer (2) or the turn ratio of primary and secondary coil.

4. according to the described millimeter wave amplifier unilateralization of claims 1 to 3 any one network, it is characterized in that, described common source structure amplifier (1) adopts silica-based complementary mos integrated circuit technique to realize.

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