Differential Power Divider Research Articles

A 28-GHz Four-Channel Beamforming Front-End IC With Dual-Vector Variable Gain Phase Shifters for 64-Element Phased Array Antenna Module

A 28-GHz fully differential four-channel beamforming front-end IC with variable gain phase shifters (VGPSs) is presented, of which orthogonal phase and gain control is achieved in a single block using the proposed dual-vector synthesis technique. This greatly reduces chip size, power consumption, and calibration complexity. The antenna switch embedded in the front-end matching network minimizes degradation of the transmitter (TX) efficiency and receiver (RX) noise figure. The multi-mode power amplifier (PA) with a built-in linearizer is presented to have high efficiency and linearity for all power modes, which reduces power consumption during gain control. Also, a differential four-way power divider and an single pole double throw (SPDT) switch are introduced in the common path, which has a small chip size and a low insertion loss. By adopting differential structures for all components in the four-channel IC, the effect of parasitic grounding inductances due to bonding and package is minimized. Thanks to the proposed dual-vector VGPS, the rms gain error of 0.21 dB and the peak phase variation of ±1.7° are achieved during phase control and gain control, respectively, without any calibration. The four-channel front-end IC also achieves rms phase error of only 1.4° during the simultaneous phase and gain control without any calibration. It has a TX OP1dB of 13.3 dBm and the highest linear output power of 7.2 dBm with 400-MHz 64-QAM fifth-generation (5G) new radio (NR) signals with 9.6-dB peak-to-average power ratio (PAPR). Also, this article presents a 64-element brick-type phased array antenna using four-channel core chips. It shows a high effective isotropic radiated power (EIRP) of 54.4 dBm at 28 GHz. An over-the-air link is demonstrated with a competitive data rate of 4 Gb/s using 64-QAM waveforms over all scan angles at a distance of 100 m.

A 90‐ to 115‐GHz superheterodyne receiver front‐end for W‐band imaging system in 28‐nm complementary metal‐oxide‐semiconductor

SummaryIn this paper, a broadband superheterodyne receiver (RX) front‐end for millimeter‐wave (mm‐Wave) imaging radar is presented. Realized in 28‐nm CMOS technology, the proposed RX incorporates a wideband low‐noise amplifier (LNA), double‐balanced passive mixers for the dual down‐conversion, a differential power divider, a differential intermediate frequency filters, a current‐mode‐logic divider‐by‐2, and a local oscillator buffers. Wideband technique and layout optimization are taken into consideration in the RX. A four‐stage LNA is devised to realize the high gain and low noise figure (NF) with a common‐gate input stage and three pseudodifferential common‐source stages. Optimized transistor layout and capacitor neutralization technique are developed to improve gain and noise performance. Transformer‐based matching networks with the peak‐staggered technique are adopted in the LNA to achieve a flatter gain response with a wider bandwidth (BW). The passive double‐balanced mixers are implemented with a highly symmetrical layout for broadband down‐conversion. Simulation results show that the mm‐Wave RX front‐end exhibits a BW ranging from 90 to 115 GHz. The simulated NF of our RX is 4.7 dB at 86 GHz. With a supply voltage of 1 V, the presented RX consumes 88.2‐mW power and occupies a chip size of 1.6 × 0.5 mm2 including all the testing pads. The proposed RX is suitable for W‐band imaging systems.

Dual-Polarized Filtering Magneto-Electric Dipole Antenna Arrays With High Radiation-Suppression Index for 5G New Radio n258 Operations

In this communication, a dual-polarized filtering magneto-electric dipole (FMED) antenna and arrays are proposed for 5G n258 (24.25–27.5 GHz) operations. The FMED antenna was devised to incorporate filtering mechanisms using a built-in substrate integrated waveguide (SIW)-based filter plus slot-and-notch etching on the dipole element. As such, lower and upper radiation cutoffs and nulls were produced and tuned, independently. To overcome the problem of “high selectivity” of a filtering antenna that has not been correctly quantified and thus has no comparison, a new skirt measure metric named as radiation suppression index is initiated here. Design steps of the FMED element and novel feeding techniques are elaborated, where the SIW-based series-parallel slot-coupled feeders and the slot-coupled differential power divider were conceived for large-size array, to combat with the insertion losses. A prototype of 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 FMED array was implemented and tested for experimental verification. A high gain of 16.8 dBi ± 1.4 dBi with a 3 dB gain bandwidth of 24–27.7 GHz and a radiation efficiency of 78% were accomplished.

A 5.8 GHz Four-Channel RF Beamforming IC Based on a Vector Modulator for Wireless Power Transmission

A 5.8GHz four-channel transmitter RF beamforming IC based on a vector modulator fabricated via the 130 nm RF CMOS process is presented here. The vector modulator controls the gain and phase independently by steering the tail current sources of a Gilbert-cell-based vector synthesizer. It offers 8-bit phase control for 360 ∘ and 4-bit gain control for a 20 dB dynamic range, with the size not depending on the control bits. A four-way differential RF power divider is introduced to implement the four-channel IC, in which off-chip ground bonding inductance is resonated out through the introduction of additional capacitances to a λ/4 impedance transformer of a four-way Wilkinson divider to reduce the insertion losses and errors. The measured total RMS gain error of the vector modulator is 0.312 dB and the total RMS phase error is 0.329 ∘. It shows 20 mW DC power consumption per channel, 5.19 dBm OP1dB, and a 3 dB gain overall including 6 dB of dividing loss.

Millimeter-Wave Multi-Band Reconfigurable Differential Power Divider for 5G Communication

A differential four-way power divider for 24 to 30 GHz and a frequency reconfigurable differential four-way power divider for 24 to 30 GHz and 37 to 43.5 GHz are presented. The differential structure provides sound virtual grounds in a multiple-channel chip. Both circuits have a four-way Wilkinson power divider (WPD) configuration based on lumped elements that provide small chip sizes. The first one has a small core chip area of 0.09 mm², a small insertion loss of 0.93 to 1.94 dB, and the port-to-port isolation of 19.1 to 25.6 dB from 24 to 30 GHz. It has a small amplitude and phase differences at four outputs. The second one allows frequency-reconfigurable operation by switching inductances and capacitances to cover widely separated frequency bands (5G NR n257-n261 bands). In addition, switched capacitors (SCs) are inserted to resonate out the parasitic series inductances in isolation resistors at both bands of 24-30 GHz and 37-43.5 GHz. It has a core chip area of 0.168 mm², insertion losses of 1.65-1.89 dB at 24 to 30 GHz and 2.04-2.70 dB at 37 to 43.5 GHz, respectively. The port-to-port isolations are 23.4-37.6 dB at 24 to 30 GHz and 22.6-28.4 dB at 37 to 43.5 GHz.

Multi-way differential power divider with microstrip output interfaces

Abstract The design and implementation of planar multi-way differential power dividers remain a challenge in terms of the compactness and especially, for the achievable characteristic impedance of the quarter-wavelength transformer when considering large number of outputs. In this work, the double-sided parallel stripline is recommended to realize such a power divider with out-of-phase outputs, and explicit design methods are provided. The proposed multi-way power divider was developed without the use of lump elements on a single substrate. For system applications, a prototype operating at 41.6 MHz with 12 pairs of out-of-phase outputs that utilize the microstrip line as the output interfaces was fabricated and examined. At the center frequency of 41.6MHz, the developed prototype measured insertion losses akin to 14.3 dB as compared with the theoretical data of 13.8 dB. The attainable impedance bandwidth ranges from 10 MHz to 80 MHz under a magnitude imbalance of ±0.3 dB. The isolations of the adjacent outputs are about 13.1 dB as compared with the theoretical values of 14.428 dB, and are better than 34 dB for more distant ones. Parameter measurements are in good agreement with the numerical predications, thus demonstrating the realization of the proposed multi-way power divider.

In brief

PAGE 632 Chinese researchers propose a symbol cyclic reconstruction scheme for universal-filtered multi-carrier systems (UFMC). The overlap-add technique is used to lower the computational complexity of the system transmitter, with ISI cancellation used at the receiver to remove interference between neighbouring symbols. Simulation results show the superiority of the scheme over state-of-the-art systems. PAGE 616 Researchers from Iran present a monitoring technique for tracking the state-of-health of batteries, suitable for use in battery management systems. The method can detect early degradation of batteries by monitoring the switching and battery transitions in a battery management system. Experiments on a typical charge balancing circuit verify the performance of the technique. Block diagram of SCR-UFMC with multipath fading channels. PAGE 589 Indian researchers propose a novel estimation technique for a noise-influenced electronic circuit, unifying the Carleman linearisation with the Fokker-Planck equation for Itô's Stochastic Differential Equations. Numerical simulation results are presented for a benchmark tunnel diode oscillator circuit. The method may prove useful for estimating state trajectories under the influence of randomness when observations are not possible. Laboratory test bench. PAGE 612 A collaboration of researchers from Japan present an evaluative study on the current and luminance characteristics of powder electroluminescent devices prepared on gravure offset-printed invisible Ag-grid electrodes. Results show that the luminance is strongly dependent on the transparency and light-extraction efficiency of the Ag-grid electrodes. Flow of the proposed estimation technique.. PAGE 609 Researchers from China propose a wideband differential filtering power divider, using a three-lined coupled structure with multiple lumped elements. Compared with other differential filtering power dividers, the proposed design shows the advantages of a wide bandwidth, compact size and low insertion loss. A prototype validates the simulated results. Optical microscopy image of the emitted light from PELDs on the Ag-grid electrodes. Photograph of the proposed wideband differential filtering power divider.

Compact wideband differential filtering power divider based on three‐line coupled structure with lumped elements

A wideband differential filtering power divider using three-line coupled structure with multiple lumped elements is proposed. The equal power division ratio, filtering response, isolation and common-mode suppression are mainly derived from the symmetrical structure, three-line coupled lines with capacitors, resistors and the short lines along the vertical symmetrical line, respectively. Compared to the reported differential filtering power dividers, the proposed design shows advantages of wide bandwidth, compact size and low insertion loss (IL). A prototype with the small size of 0.5λ g × 0.08λ g (λ g is the guided wavelength at the centre frequency) was designed for demonstration, which exhibits the 3 dB fractional bandwidth of 79.2% and the minimum IL of 0.48 dB.

Printed RGW Circularly Polarized Differential Feeding Antenna Array for 5G Communications

In this paper, a differential feeding circularly polarized antenna array implemented with printed ridge gap waveguide technology for millimeter-wave applications is proposed. The differential feeding power divider is designed based on aperture coupling to achieve a stable 180° phase imbalance over 20% operating bandwidth at 30 GHz with sufficient matching level. This power divider is deployed to excite and test the proposed differential feeding antenna. The proposed antenna is formed by a rectangular aperture having a circular-shaped polarizer consisting of patch surrounded by an open-end ring, which is differentially fed. This polarizer is deployed to achieve a circular polarization radiation through a 10 % frequency bandwidth. A high-gain antenna array is implemented by extending the aperture size to have four radiating elements. The antenna array is fabricated, where the experimental results verify a −10 dB impedance bandwidth from 27.7 to 32.4 GHz (15.6%). Moreover, a 3 dB axial ratio bandwidth over 10 % is achieved, which is sufficient enough to cover the operating bandwidth of potential 5G applications at 30 GHz. The fabricated prototype achieves a 3 dB gain of 14 dB, with low cross polarization and a radiation efficiency higher than 84% over the whole operating frequency bandwidth.

Substrate integrated waveguide differential filtering power divider with good common‐mode suppression and high selectivity

A filtering differential power divider based on the substrate integrated waveguide (SIW) technology is proposed for the first time, featured by good common-mode suppressions and high selectivity. A rectangular SIW cavity, which is connected with differential inputs and operates in a balanced diagonal TE102 mode, is utilised to achieve the power division function. It also works with rectangular SIW cavities, which resonate in balanced TE102 modes, to obtain good common-mode suppressions for all cases. Meanwhile, electric negative cross-couplings are introduced to improve the frequency selectivity of the proposed filtering power divider. A prototype operated in the X-band has been developed for a demonstration. Good agreement between simulated and measured results is obtained.

A novel differential filtering SIW power divider with high selectivity

A novel differential power divider with bandpass filtering response using the substrate integrated waveguide (SIW) technology is presented. An SIW resonant cavity operated in a balanced resonant mode with odd symmetric electric field distribution is utilized to provide both balanced inputs/outputs and expected common-mode (CM) suppression in a certain band. Meanwhile, by properly constructing the cross-coupled topology of SIW resonant cavities, the proposed differential power divider achieves a high-selectivity bandpass filtering response with two transmission zeros on both sides of the passband. The differential power divider is designed and prototyped on a single-layer printed circuit board (PCB). The measured center frequency is at 10.6 GHz with 490 MHz 3-dB bandwidth. A good CM suppression can also be achieved within the operating band. The measured in-band differential-mode imbalance for magnitude is ±0.3 dB, while for phase is 0°–4°. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2015.

Compact differential power divider with enhanced bandwidth and in‐phase or out‐of‐phase output ports

A differential power divider using coupled microstrip line is proposed. The differential-mode response can be controlled by the odd-mode of the coupled microstrip line and resistors. Compared with the reported differential power dividers, the proposed one shows the advantages of compact size, wide bandwidth and easy connection with radio frequency (RF) chips. Furthermore, both in-phase and out-of-phase output ports can be realised using different connection ways. Two prototypes have been fabricated with the same size of 0.185λg × 0.245λg, one with in-phase output ports and the other with out-of-phase output ports, showing the same minimum insertion loss of 0.2 dB and relative frequency bandwidths for |Sdd11| <−15 dB of 75 and 78%, respectively.

Broadband Eight-Way Differential SIW Power Divider with Bandpass-Filtering Response Using Novel Hybrid Multiple-via Probe and Multiple Radial Slots

A broadband eight-way differential substrate integrated waveguide (SIW) power divider with bandpass-filtering response by using novel hybrid multiple-via probe and multiple radial slots has been presented in this paper. The novel hybrid multiple-via probe are employed to achieve broadband impedance matching, while the multiple radial slots are used to improve the out-of-band rejection level. An eight-way differential SIW power divider with bandpass-filtering response is designed, fabricated, and measured. The measured results agree with the simulated ones closely in the desirable frequency range. The measured average insertion loss of the eight-way power divider is approximately 9.3 dB and input return loss is greater than 15 dB from 3.2 to 8.1 GHz. Moreover, the out-of-band rejection band with more than 25 dB attenuation from 9 GHz to more than 11 GHz is observed. A maximum amplitude imbalance of $$\pm 0.7\,\hbox { dB}$$ ± 0.7 dB is observed over the entire operating frequency range.

A 40-50-GHz SiGe 1 : 8 differential power divider using shielded broadside-coupled striplines

This paper presents a 1 : 8 differential power divider implemented in a commercial SiGe BiCMOS process using fully shielded broadside-coupled striplines integrated vertically in the silicon interconnect stackup. The 1 : 8 power divider is only 1.12 x1.5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> including pads, and shows 0.4-dB rms gain imbalance and <3deg rms phase imbalance from 40 to 50 GHz over all eight channels, a measured power gain of 14.9 plusmn0.6 dB versus a passive divider at 45 GHz, and a 3-dB bandwidth from 37 to 52 GHz. A detailed characterization of the shielded broadside-coupled striplines is presented and agrees well with simulations. These compact lines can be used for a variety of applications in SiGe/CMOS millimeter-wave circuits, including differential signal distribution, miniature power dividers, matching networks, filters, couplers, and baluns.