DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Summary of the Invention
The invention provides a coupler device for phased-array systems in which a tunable/variable-gain amplifier generates two intermediate signals whose relative amplitudes are adjusted so that, when fed into a 90° hybrid coupler, the two coupler outputs have a controllable but fixed phase difference (used for beamforming without excessive power divider loss). In another embodiment, the device further includes a power divider, Marchand baluns, variable-gain amplifier chains, and switches so that either inverted or non-inverted versions of the divided signals are amplitude-weighted and combined in the coupler to realize precise, adjustable phase shifts between array paths.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-9 are rejected under 35 U.S.C. 102(a)(2) as being unpatentable over Wu et al., (US 2025/0350024 A1, effectively filed on July 8, 2019 before the effective filing date of the current invention October 16, 2023).
Regarding claim 1, which recites a coupler device for a phased-array system comprising:
(1) a tunable amplifier that converts an input signal to a first and a second intermediate signal; and
(2) a coupler having first and second input ports for receiving those intermediate signals and first and second output ports that output signals separated by a fixed phase angle.
Wu et al. discloses, in FIG. 1 and ¶¶ [0031] – [0035], a frequency-tunable bi-directional vector modulator (100) built around a frequency-tunable quadrature-phase coupler (101), an I-path input matching network (IMN 110) and bi-directional variable gain transistor core (BD-VGTC1 121), and a Q-path input matching network (IMN 120) and bi-directional variable gain transistor core (BD-VGTC2 125).
Coupler 101 receives an input RF signal and splits it into an I signal and a Q signal that are 90 degrees apart in phase. The two BD-VGTC cores amplify these intermediate signals and feed a shared output matching network (OMN 130) that recombines them on a common node to produce the desired output.
Wu et al. thus expressly teaches both the tunable amplifier and the quadrature coupler having outputs separated by a fixed phase angle, satisfying all limitations of claim 1.
Regarding Claim 2 it requires that the tunable amplifier adjust the first and second gains of the intermediate signals to adjust the fixed phase angle.
Wu et al. discloses in ¶¶ [0043] – [0045] that the output phase φ = tan⁻¹(β/α) is a function of the individual gain-control values (α and β) on the I and Q paths, respectively, thereby providing fine phase-angle adjustment via gain control. Accordingly, Wu et al. anticipates claim 2.
Regarding Claim 3 additionally it specifies that “a second difference between the first output signal and the input signal is +φ⁄2, and a third difference between the second output signal and the input signal is −φ⁄2, and φ denotes the fixed phase angle.”
As shown in Wu et al., FIG. 1 and described at ¶¶ [0031] – [0035] and [0043] – [0045]:
- The frequency-tunable quadrature-phase coupler 101 splits the input signal into two equal-amplitude signals, the I and Q channels, having a relative phase difference of 90 degrees (φ = 90°).
- In that configuration, the phase of the I branch signal (at node between IMN 110 and BD-VGTC1 121) is approximately +φ⁄2 ( +45° ) relative to the reference phase of the input, while the phase of the Q branch signal (at node IMN 120 → BD-VGTC2 125) is −φ⁄2 ( −45° ).
- The resulting two intermediate signals are combined at the shared output matching network (OMN 130 / common node) to yield a total phase differential of φ = 90°.
Paragraph [0043] further defines this mathematically as Output = α · I + β · Q, where the phase shift φ = tan⁻¹(β/α) represents the total phase separation. The I and Q paths thus maintain equal-and-opposite half-phase differences (±φ⁄2) from the input reference, precisely as claimed.
Regarding Claims 4–6, Wu et al., Figs. 2A and 2B and ¶¶ [0039] – [0040], disclose complementary differential transistor cores (211/212/213/214) forming the bidirectional amplifier. Input matching networks (IMN 110/120) and output matching network (OMN 130) explicitly provide impedance matching to system impedance, meeting the structural recitations of these claims.
Regarding Claim 7, Wu in §0037 – §0038 describes operation with high efficiency, reduced trace loss, active current combining, and “no switch loss,” evidencing both power conservation and signal amplification as recited.
Regarding Claims 8 – 9, Wu et al., in Fig. 7 and §0050 – §0051, identifies the frequency-tunable Lange (hybrid) coupler 700 configured with four coupled transmission lines, each corresponding to the claimed first through fourth transmission lines connecting the respective input and output ports. The coupler operates as a 90-degree hybrid, satisfying all limitations of these claims.
Wu et al. (Figs. 1, 2A, 2B, and 7; §0031– §0051) clearly describes every limitation of independent claim 1 and dependent claims 2 through 9.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 10-20 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US 2025/0350024 A1) in view of Milano (WO 2012/093392 A1) and further in view of Kim (US 2016/0142026 A1) where specifically identified below.
Regarding Claim 10 Wu et al. (§0031–§0035, Fig. 1) teaches dividing an input signal using a quadrature-phase coupler (101) into I and Q paths, processed by variable gain transistor cores (BD-VGTC 121/123/125/127), and recombined in a shared output matching network (OMN 130) functioning as an active combiner/splitter.
However, Wu does not explicitly disclose a balun or distinct power divider with differential inversion preceding the vector modulator.
Milano (WO 2012/093392 A1) (see pp. 13–15, Figs. 3, 11, 13) teaches Wilkinson and 3 dB quadrature couplers that divide an input into multiple branches for phased-array radiators; Milan’s passive manifold specifically employs 180° Marchand baluns and Wilkinson splitters to feed balanced receivers and transmitters.
It would have been obvious to a person of ordinary skill in the art (POSITA) before the effective filing date of the invention to incorporate Milano’s discrete power divider/baluns as the front-end in Wu’s bi-directional modulator in order to generate differential I/Q signals with defined amplitude and phase balance—an expected and routinely implemented improvement in mm-wave phased-array networks.
Therefore, Claim 10 is obvious over Wu in view of Milano.
Claim 11 adds that the first and second output signals exhibit a fixed phase angle between them.
Wu expressly teaches this: its quadrature-phase coupler 101 provides a 90° phase difference between I and Q outputs (¶ [0031]–[0032]; Fig. 7 shows "FREQ TUNABLE QUADRATURE PHASE COUPLER"). The resultant output signals retain a fixed phase separation established by the coupler. Thus, claim 11 is obvious over Wu alone.
Claim 12 specifies that the phase angle may be changed by adjusting a first and second gain. Wherein Wu (§0043–§0045, Figs. 3A – 3B), disclose output phase φ = tan⁻¹(β/α) where varying the differential gain of I and Q paths (BD-VGTCs) changes both amplitude and phase. Hence, the phase shift is gain-dependent. Thus, claim 12 is obvious over Wu alone.
Claim 13 introduces first and second switches between each balun and amplifier, to select an inverted or non-inverted input. Wherein Wu (Fig. 4, §0047) teaches an invertible polarity switch realized by single-pole-double-throw devices that reverse current flow or interchange complementary inputs within the BD-VGTC path. The specific placement of the polarity inversion switch (between balun and amplifier) represents a design-choice modification performing equivalent polarity selection already taught by Wu.
Furthermore, Milano (WO 2012/093392 A1) (Figs. 8–10, pp. 15–16) discloses Wilkinson and Marchand couplers including selective switchable sections for 180° phase inversion in multi-section couplers. Substituting those switches at the balun interface would have been obvious to provide selectable inversion. Accordingly, claim 13 is obvious over Wu in view of Milano.
Claim 14 recites that each amplifier comprises an input stage, gain stage, and output stage connected in series. Wherein Wu’s BD-VGTC amplifier cores (§0039–§0040; Figs. 2A–2B) include input differential transistor pairs (input stage), cascade transistors (gain stage), and output drain nodes coupled to matching networks (OMN, output stage)—collectively meeting this functional description.
To the extent broader definition is required, Kim (US 2016/0142026 A1) (§0055–§0061, Fig. 5) discloses an RGC amplifier possessing an input transistor, feedback/gain transistor, and output buffer—precisely three cascaded stages used in optical and RF pre-amplifiers for linear trans-impedance gain.
It would have been obvious to organize Wu’s transconductance amplifier elements into distinct input/gain/output segments consistent with Kim’s cascade configuration to improve stability and linear range. Hence, claim 14 is obvious over Wu in view of Kim.
Claim 15 specifies that the stages are common-gate (input), common-source (gain), and common-drain (output). Wherein Wu already employs common-source differential transistor pairs in BD-VGTCs and cascode transistors acting as common-gate devices (¶ [0039]; Fig. 2A). Integrating an output buffer (common-drain) for impedance matching is standard practice (Wu, §0036; Kim, §0070). Combining Kim’s explicit depiction of these stage types (Fig. 7) with Wu’s BD-VGTC achieves precisely the configuration claimed. Therefore, claim 15 is obvious over Wu in view of Kim.
Claim 16 introduces a variable resistor between the input and gain stage to adjust gain. Kim (§0068–§0071, Fig. 7) describes a source-degeneration resistor Reon 720 whose value is dynamically controlled by a bias voltage to vary amplifier gain—directly analogous to the variable resistor recited. Wu discloses variable gain via transistor biasing; combining Kim’s adjustable resistor element with Wu’s gain control yields predictable, well-known gain tuning. Thus claim 16 is obvious over Wu in view of Kim.
Claim 17 specifies that the coupler is a 90-degree hybrid coupler. Wu explicitly discloses a “frequency-tunable 90-degree Lange coupler 700” functioning as a quadrature (hybrid) coupler (Fig. 7; §0050). Therefore, claim 17 is obvious over Wu alone.
Claim 18 recites that the first and second baluns are Marchand baluns. Milano (WO 2012/093392 A1, Figs. 8 – 10) teaches a Marchand 180° directional coupler for balanced feed networks (§0008–§0010 of Milano). Such baluns are functionally equivalent to differential couplers used in Wu. Substitution of Milano’s Marchand structure for Wu’s underlying coupler yields predictable results—balanced signal transformation—well within the skill in the art. Thus, claim 18 is obvious over Wu in view of Milano.
Claim 19 recites that the power divider is a Wilkinson power divider composed of two sets of coupled lines each a quarter wavelength long. Milano (WO 2012/093392 A1, (Figs. 3 – 4, 13–15) discloses Wilkinson power dividers employing λ/4 lines as manifold feeds for planar phased-array antennae. Incorporating such a conventional Wilkinson divider as the front-end of Wu’s tunable coupler circuit is a routine design implementation producing the same impedance-matched power splitting at mm-wave frequencies. Therefore, claim 19 is obvious over Wu in view of Milano.
Claim 20 further specifies that each coupled-line section in the Wilkinson divider has a length equal to a quarter wavelength of the radio-frequency (λ/4) signal. Milano’s disclosure inherently includes that dimensional relationship (§0010; Figs. 3 – 13: port pairs with ¼λ lines at ~60 GHz). Designing the divider with λ/4 segments is a basic physical constraint of Wilkinson dividers known to POSITA and therefore inherent to Milano’s device. Consequently, claim 20 is obvious over Wu in view of Milano.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HAFIZUR RAHMAN whose telephone number is (571)270-0659. The examiner can normally be reached M-F: 10-6.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Andrea Lindgren Baltzell can be reached on (571) 272-1769. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
/HAFIZUR RAHMAN/Primary Examiner, Art Unit 2843.