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In this paper, a new design concept of Schiffman phase shifters under the operation of the second phase period in frequency domain is presented and analyzed. By investigating phase properties of the C-section structure, we first find that its second phase period is another independent and distinctive working region for Schiffman phase shifter, in addition to its first phase period. In contrast to traditional counterparts working on the first phase period, which are suitable for small phase shift from 0° to 90°, the Schiffman phase shifters on the second phase period are suitable for the large phase shift from 90° to 180°. It is because of the opposite phase variation property that the electrical length of reference line gets shortened as the phase shift value increases. Compared with the first phase period, the second phase period can achieve wider phase shift bandwidth under the same coupling degree. This feature is believed to be very useful in the limited realizable coupling degree cases. In this context, the closed-form synthesis formulas of Schiffman phase shifter on the second phase period are presented. Meanwhile, detail theoretical analysis of the phase shift bandwidth and phase deviation is carried out. In final, two Schiffman phase shifters on the first and second phase periods are designed and fabricated to validate our proposed concept and approach in the experiment. [ABSTRACT FROM AUTHOR]

This paper addresses the miniaturization of microwave vector network analyzers (VNAs) and the future vision of the VNA on a chip. Therefore, a highly integrated two-port VNA with a multioctave bandwidth from 4 to 32 GHz is presented. The proposed system is based on a fully integrated radio-frequency frontend consisting of a two-port stimulus, a four-channel heterodyne receiver, and a wideband testset. The testset is comprised of on-chip multisection directional couplers. The chip is operated inside a hardware demonstrator using a 16-term calibration procedure. The measurement of arbitrary devices under test is in excellent agreement with commercial measurement equipment and showed a mean deviation from the reference measurement of 0.17 dB and 1.29° regarding the forward transmission of a coaxial 30-dB attenuator. The system and receiver dynamic ranges are 44–77 and 82–101 dB at a resolution bandwidth of 100 kHz over the full system bandwidth. The measurements are highly repeatable and are robust against drift over time. As a proof of concept, the developed integrated network analyzers are utilized in a biomedical sensing scenario with an external and an on-chip sensor. Both approaches showed good sensitivity regarding the mixture ratio of binary solutions of ethanol and methanol. [ABSTRACT FROM PUBLISHER]

This paper presents a highly symmetric 1\! :\! n concentric vortical transformer (CVT) technology, which can be implemented with slab inductors. The CVT and several widely used planar transformer structures are analyzed to show the characteristic distinction of the CVT. The proposed CVT was developed in an integrated passive device technology along with the popular distributed active transformer (DAT) for comparison. Under the same real-part impedance transformation ratio at 2.4 GHz, the outer diameter of the CVT is only 48% of the DAT. Moreover, 89.4% transformation efficiency and 191% - \1-dB fractional bandwidth are achieved by the CVT from a high coupling coefficient of 0.9. The symmetric nature of the CVT makes it capable of achieving far less variation than the DAT in resistance and reactance among multiple input ports when used for power combining. [ABSTRACT FROM PUBLISHER]

This paper introduces a new design process for miniature coupled resonator filters with mixed couplings, which can better preserve wideband response matching with coupling matrix prototype. A special type of matrix transformation is introduced in this paper to transform the coupling matrix into a configuration that consists of an equal number of capacitive and inductive main couplings. Based on this, lumped-element circuit models can be produced. Then, by using \pi to \bf T transformations for some parts of the circuit, all the elements have realizable values. A miniature bandpass filter with a fractional bandwidth of 20% of this type based on N\times N coupling matrix is demonstrated with both simulated and measured response. The filter is implemented using multilayer liquid crystal polymer circuit technology and has a compact size of 0.0294\lambda g \times 0.0303\lambda g \times 0.00052\lambda g, where \lambda g is the guided wavelength at the center frequency of 250 MHz. [ABSTRACT FROM AUTHOR]

We propose a wideband lumped element directional coupler using lossy negative capacitance (NCAP). NCAP provides a broadband resonance effect combined with passive inductors and capacitors in a circuit, enabling the coupler to exhibit wideband directivity performance. In addition, a 3-dB loss in the NCAP enhanced the bandwidth at the expense of the transmission gain, which decreased by only 0.3 dB. The proposed coupler was implemented in the IBM 7RF 180-nm CMOS technology. The size of the core chip is $1180\,\,\mu \text {m} \times 570\,\,\mu \text{m}$. The designed NCAP provides a capacitance of −13 pF using a supply voltage of 2.7 V and a current of 9.6 mA. The coupling was designed to be −10 dB at the center frequency of 1 GHz. The bandwidth was defined by the frequency range, which exhibited a directivity of more than 30 dB. The S-parameter measurements showed an absolute bandwidth ranging from 0.86 to 1.12 GHz, and a fractional bandwidth of 26%. In the bandwidth, the coupling had a 0.5-dB variation, the transmission loss was smaller than 2.14 dB, and the noise figures were 1.8–2.5 dB. [ABSTRACT FROM AUTHOR]

This paper proposes a novel class of wideband metal cavity multiple-mode bandpass filters (BPFs), consisting of a triple-mode filter and a quadruple-mode filter. Two TE11 degeneration modes in a single metal cavity are excited by using an off-centered approach instead of a traditional corner-cut approach. They work together with the TM10 mode to constitute a three-pole wide passband with a fractional bandwidth of 30% at the central frequency of 3.2 GHz. Moreover, an off-centered metal cylinder can properly excite an extra TM11 mode in the passband. As such, this TM11 mode, TM10 mode, and a pair of degeneration TE11 modes can be simultaneously utilized to form a quadruple-mode BPF. Compared with the triple-mode BPF, the quadruple-mode BPF has better performance in term of the steepness of rejection skirt. The fractional bandwidth of this BPF can achieve up to 31%. In final, the two proposed BPFs are fabricated by using the silver plated aluminum technology. Measured S-parameter frequency response and group delay have satisfactorily matched with the simulated results. [ABSTRACT FROM PUBLISHER]

Two new wideband in-phase and out-of-phase balanced power dividing/combining networks are proposed in this paper. Based on matrix transformation, the differential-mode and common-mode equivalent circuits of the two wideband in-phase and out-of-phase networks can be easily deduced. A patterned ground-plane technique is used to realize the strong coupling of the shorted coupled lines for the differential mode. Two planar wideband in-phase and out-of-phase balanced networks with bandwidths of 55.3% and 64.4% (\vert S{ dd21,31}\vert<4\ {\ {dB}}) for the differential mode with wideband common-mode suppression are designed and fabricated. The theoretical and measured results agree well with each other and show good in-band performances. [ABSTRACT FROM PUBLISHER]

This paper presents a new class of dual-, tri- and quad-band BPF by using proposed open stub-loaded shorted stepped-impedance resonator (OSLSSIR). The OSLSSIR consists of a two-end-shorted three-section stepped-impedance resistor (SIR) with two identical open stubs loaded at its impedance junctions. Two 50-\Omega tapped lines are directly connected to two shorted sections of the SIR to serve as I/O ports. As the electrical lengths of two identical open stubs increase, many more transmission poles (TPs) and transmission zeros (TZs) can be shifted or excited within the interested frequency range. The TZs introduced by open stubs divide the TPs into multiple groups, which can be applied to design a multiple-band bandpass filter (BPF). In order to increase many more design freedoms for tuning filter performance, a high-impedance open stub and the narrow/broad side coupling are introduced as perturbations in all filters design, which can tune the even- and odd-mode TPs separately. In addition, two branches of I/O coupling and open stub-loaded shorted microstrip line are employed in tri- and quad-band BPF design. As examples, two dual-wideband BPFs, one tri-band BPF, and one quad-band BPF have been successfully developed. The fabricated four BPFs have merits of compact sizes, low insertion losses, and high band-to-band isolations. The measured results are in good agreement with the full-wave simulated results. [ABSTRACT FROM PUBLISHER]

This paper presents CMOS distributed amplifiers (DAs) using the proposed gate–drain transformer feedback technique. The feedback allows reuse of the traveling signal to achieve a high gain-bandwidth product while maintaining low power consumption of DAs. With the folded transmission lines and patterned ground shield, the miniaturized transformer has high quality factors and a well-controlled feedback coupling coefficient. Two DAs are realized using the proposed technique in both \0.18-\mu\ m and 90-nm CMOS technologies, respectively. The \0.18-\mu\ m CMOS DA achieves a gain of 9.5 dB with a 3-dB bandwidth of 32 GHz, and the noise figure (NF) ranges from 4.1 to 7.6 dB under a power consumption of 71 mW. Under a power consumption of 60 mW, the 90-nm DA demonstrates a gain of 7 dB, a bandwidth of 61.3 GHz, and an NF below 6.2 dB up to 40 GHz. The core areas of the \0.18-\mu\ m and 90-nm designs are only 0.58 and \ 0.41 mm^2, respectively. [ABSTRACT FROM PUBLISHER]

Two novel wideband differential bandpass filters based on a T-shaped structure are proposed in this paper. Broad passband and wideband harmonic suppression for the differential/common mode can be easily achieved for the wideband differential filter without cross coupling, due to the controlled resonator frequencies of the shorted/open T-shaped structure. In addition, another more compact differential filter using cross coupling is proposed with two transmission zeros close to the passband to improve the selectivity for the differential mode. To verify the presented concept, two prototypes (\varepsilon r = 2.65, h = 0.5~\ mm) with 3-dB fractional bandwidth of 70% and 70.7% for the differential mode and insertion loss greater than 13.5 dB for common mode (0–19 GHz) are designed and fabricated. Good agreement can be observed between measured results and theoretical expectations. [ABSTRACT FROM AUTHOR]

Tightly coupled lines are difficult to realize on the conventional printed circuit board (PCB). This paper proposes two types of novel enhanced coupled-line structures appropriate for tightly coupled directional couplers and wideband filters. The proposed coupled-line structures both have a rectangular ground-plane aperture and two inserted signal strips in the aperture to increase the coupling strength significantly. No fine lines and narrow gaps are required so as to fit the conventional PCB fabrication process. More importantly, the proposed structures only need a single-layer substrate. To demonstrate the feasibility of the proposed structures, one 3-dB directional coupler and two four-pole Chebyshev filters with 0.05-dB equal-ripple bandwidths of 40% and 37% are designed and realized. The coupler and filters are fabricated on a PCB substrate with a dielectric constant of 3.58 and a thickness of 0.508 mm. Good agreement between measurements and simulations is observed. [ABSTRACT FROM AUTHOR]

In the above paper two equivalent circuits of $L_{T}-$ and $\Pi $ -types for a 90° transmission-line section (TL) are suggested only for $N = 1$. However, the design formulas for $N= n$ , where $n\ge 1$ and integer, are already published for $L_{T}$ -types and for $\Pi $ -types [3, Fig. 6(c) with $\Theta _{a}= 0^{\circ }$ ], , and the advantages for $N \ge 2$ are verified for $L_{T}$ -types in and $\Pi $ -types , , as well. [ABSTRACT FROM AUTHOR]

Two phase shifters are proposed using a multiple circular sector structure. Advantages of the design include low insertion losses and small phase variations over a wide range of operating bandwidths. The design process follows a multiobjective optimization procedure that applies computational power for circuit tuning. Performance of the phase shifters are analyzed, after fabricating and measuring for verification. The phase shifter performances are compared with other existing phase shifter configurations in terms of insertion losses and phase variations. [ABSTRACT FROM AUTHOR]