Tunable Power Divider Research Articles

Planar In-Phase Filtering Power Divider With Tunable Power Division and Controllable Band for Wireless Communication Systems

A wideband in-phase power divider with tunable power division ratio (PDR) and filtering response is presented. The proposed design is quite compact and consists of a three-line coupled structure and loaded with a pair of varactor-loaded short-ended stubs at two output terminations. A variable power division is realized by tuning the coupling factors between the centerline and sidelines of the three-line coupled structure using a pair of varactors. A varactor at the center of the loaded short-ended stub and another one connecting the end of the stub to the ground is used to control the center frequency and band of operation. A prototype is modeled using the microstrip technique and then simulated and tested. The experimental result indicates a tunability of PDR from 0.5:1 to 2:1 across wideband range of 60% and a controllable band from 35% to 63.2%, with 13% center frequency tunability, sharp passband cutoff selectivity, as well as harmonic suppression to more than 6 GHz (4 times the center frequency). Moreover, the overall loss is around 1–1.2 dB; the isolation is more than 14 dB, whereas the differential phase is less than 7° in all the investigated cases.

A Continuously Tunable Unequal Power Divider With Wide Tuning Range of Dividing Ratio

In this letter, a dividing ratio continuously tunable power divider with a wide tuning range is presented. A pair of tunable shunt stub is utilized to achieve different power dividing ratios and good input matching performance. By varying the loaded capacitance of the tunable stubs, a continuous tuning range from 1:1 to arbitrary dividing ratio can be achieved theoretically. For demonstration, a prototype circuit with the dividing ratio from 1:2 to 1:100 is designed and fabricated. Good agreement can be observed between the measured results and simulated results.

A New Coupler Structure with Phase-Controlled Power Divisions of Extremely-Wide Tunable Ranges and Arbitrary Phase Differences

This paper presents a novel structure for realizing a coupler with controllable power divisions, which is composed by two couplers and two phase shifters cascaded between them. This structure is applicable to constructing couplers with extremely-wide-range tunable power division, and the phase-difference performances can be predicted and controlled flexibly. In this paper, the rigorous design equations and methodologies are exhibited. For verification, two prototypes with rat-race and quadrature operations are fabricated and measured, and the measured results sufficiently confirm this topology to be effective and correct.

A Planar Balanced Power Divider With Tunable Power-Dividing Ratio

This paper reports on, for the first time, the design and implementation of planar balanced tunable power dividers. The wide power-dividing tuning range is obtained by using two tuning capacitors and a single control voltage. The differential-mode operation, common-mode rejection, and cross-mode conversion suppression are realized for all tuning states. Closed-form equations for design parameters are derived. For verification, a power divider operating at 1 GHz with power-dividing tuning ratio of 0.01–3.61 is designed based on the given closed-form design equations. Finally, a microstrip tunable power divider with two varactor diodes MA46H202 is fabricated and measured. The measured results are in good agreement with the simulated ones.

Design of miniaturised balun filter with tunable power division ratio and centre frequency

A miniaturised balun filter with tunable power division ratio (PDR) and centre frequency is presented. Compared with the conventional balun filter, the proposed one with a varactor diode and a slide rheostat loaded onto transmission line (TL) reduces the electrical length of TL from 180° to 108°. Meanwhile, the varactor diode and slide rheostat are also utilised to control the PDR at two output ports. Moreover, passband frequency can be tuned by controlling the varactor diodes loaded onto the dual-mode resonators. The proposed balun filter achieves a tunable power division from 1:1 to 3:1 and 28.6% wide frequency turning with better than 12 dB return loss. The total electrical size of fabricated circuit is 0.23 × 0.12 λ g .

Tunable In-Phase Power Divider for 5G Cellular Networks

A tunable power divider that operates in the 28-GHz band for future 5G mobile systems is presented. The proposed power divider can be used in the feeding network of the antenna array of a cellular network for a beamforming purpose. The proposed design is a modification of the traditional Wilkinson power divider and has the ability to change the output power division ratio continuously. To realize that, two varactor-loaded L-shaped open-ended stubs are connected to the two branch lines of the device to ensure the flatness of the power division. Moreover, two asymmetrical coupled lines are adopted in the output ports and a stepped-impedance transformer is added at the input port to enhance their matching across different power divisions and wide frequency range. A prototype is developed and tested. A tuning power ratio range from 1:1 to 1:2.3 across the band (27–29 GHz) is achieved. The return losses are more than 13 dB, while the isolation is more than 10 dB across that band. In addition, the simulated and measured amplitude and phase imbalances are less than 0.2 and 0.5 dB, and 5° and 12°, respectively, from the ideal values.

Coupled‐line directional coupler with tunable power division ratio and operating frequency

This study presents a novel planar coupled-line directional coupler with tunable both power division ratio and operating frequency, which is achieved using microstrip technology for the first time. Its tunability of the operating frequency and the power division ratio, or coupling ratio, can be independently controlled by the bias voltages. Moreover, it can simultaneously maintain perfect port match and isolation. On the basis of the even–odd mode analysis method, both the closed-form analytical equations and parameter discussions are provided to facilitate the practical design. An experimental prototype of the tunable coupler is simulated, fabricated, and measured to demonstrate how it works. The measured results indicate that power division ratio can vary from 0.35 (9 dB) to 0.71 (3 dB) when operating frequency ranges from 0.55 to 1.48 GHz (91.63%) while power division ratio varies from 0.35 (9 dB) to 1 (0 dB) when operating frequency is fixed at 1 GHz, which validated the reliability of the proposed model.

A Compact Tunable Power Divider With Wide Tuning Frequency Range and Good Reconfigurable Responses

A compact tunable power divider is proposed in this brief. The power divider can achieve a wide frequency tuning range and good matching and isolation performances. Theoretical equations for the characteristic impedance and the electrical length of the power divider are derived. For demonstration, a prototype working at 1.5 GHz as the center frequency is designed and fabricated. The measured results show that the power divider can be effectively tuned within the frequency range of 104% (0.83–2.4 GHz) with a return loss and isolation better than 20 dB and insertion loss varying between −3.3 dB and −3.5 dB.

Wideband Tunable In-Phase Power Divider Using Three-Line Coupled Structure

An in-phase power divider (PD) with a wide tuning range for the power division ratio across one octave bandwidth is presented. The device uses a quarter-wavelength three-line coupled structure with controllable coupling factors using two centrally connected varactors. One terminal of the central coupled line is connected to the input port, whereas its other terminal is grounded. The two coupled side lines are connected to the output ports, whereas an isolation resistor connects their other ends. The mode theory is used to analyze the performance and predict the initial dimensions. To validate the design, a prototype of dimensions 30 $\times$ 20 is built on Rogers RO6010 substrate and tested. The results indicate a tunable power division ratio from 1:1 to 1:2.4 with less than 0.5 dB additional insertion loss across the frequency band 0.7–1.4 GHz. The device has more than 10 dB return loss at all the ports and more than 15 dB isolation between the output ports. The two output signals are in-phase across the whole band with less than 8 $^{\circ}$ differential phase imbalance.

A Novel Coupled-Line Tunable Wilkinson Power Divider With Perfect Port Match and Isolation in Wide Frequency Tuning Range

In this paper, a novel coupled-line tunable Wilkinson power divider with perfect port match and isolation in a continuously tunable passband is presented. The proposed tunable power divider consists of an isolation resistor, two coupled lines, and two types of varactors. By providing these varactors with suitable bias voltages, the operating frequency of the proposed power divider can be flexibly changed as desired. Meanwhile, perfect port match and isolation are maintained at all tunable operating frequencies. After applying the even-odd mode analysis method, the closed-form equations of the design parameters are derived to illuminate the effects on the minimum and maximum operating frequencies. These equations exhibit that the proposed power divider has a wide frequency tuning range and a high tunability (more than 110% in ideal conditions). Owing to the limitation of manufacturing process, a microstrip power divider with a tunable frequency of 0.54–1.41 GHz (89.23%) is designed and simulated based on the provided closed-form equations. The measured results show a frequency tuning range from 0.56 to 1.39 GHz (85.13%) with a more than 20-dB return loss and isolation in the entire tuning range, agreeing well with the simulation results.

Modified Wideband Marchand Balun With Tunable Power Division Ratio and Constant Phase

A balun with a wide tunable power division ratio and constant phase across a wide frequency band is presented. The proposed design is a modification of the traditional Marchand balun with a varactor and series resistor loaded at the central point of the two connected pairs of coupled lines. The varactor is used to control the power division ratio at two output ports, whereas the resistor is used to stabilize the power division across a wide operational bandwidth. The achievable power division ratio and differential phase are investigated for different band ranges. A prototype is designed, fabricated, and tested. The results indicate a tuning power ratio range from 1:1 to 3.5:1 across 80% fractional bandwidth (1.2–2.8 GHz) with more than 10 dB return loss and less than 9 $^{\circ}$ differential phase.

High selectivity tunable filtering power divider based on liquid crystal technology for microwave applications

A novel electrically tunable filtering power divider, based on liquid crystal (LC) technology, is designed and experimentally demonstrated in this paper. Using low-cost T-shaped inverted-microstrip structures integrated with two dual-mode open-loop resonators, the tunable power divider possesses bandpass-filtering frequency response. Moreover, transitions between inverted-microstrip and microstrip structures are specifically designed at the I/O ports for the self-packaged. The experimental results indicate that the central frequency can be tuned from 5.75 to 6.25 GHz, i.e. a relative tuning range of 8.3%, the 3-dB bandwidth is 6.8 ± 0.2% over the whole tuning range, and the maximum amplitude and phase imbalance are less than 0.8 dB and 2.5°, respectively. In addition, the proposed filtering power divider has three transmission zeros to improve the frequency selectivity.

Back-to-Back Microstrip Antenna Fed With Tunable Power Divider

A design for microstrip antennas with reconfigurable radiation pattern is described. Dual stacked patch antennas and one tunable power divider are involved in the reconfigurable design. The two antennas are arranged by a back-to-back configuration, and they are, respectively, excited by the outputs of the power divider composed of a quasi-lumped coupler and two varactor diodes. By controlling the dc voltage of the varactors, the ratio of two outputs of the power divider can be varied between 0 and 13 dB so that the radiation patterns generated by the two antennas are changed. A prototype operating at 2.45 GHz frequency band is implemented and tested. Experimental results demonstrate that the radiation of the prototype in the H-plane can be switched between an omnidirectional pattern and broadside patterns with various front-to-back ratios.

Tunable quasioptical power dividers operating in the millimeter wavelength range

Circuits and principle of operation of quasioptical power dividers based on two-row periodic structures, formed by grids of metal bars and a dielectric waveguide placed along their longitudinal axis, are described. The experimental studies of power divider prototypes in a frequency range of 60–80 GHz have shown a possibility of regulating the emitted power level in the main divider arm by changing longitudinal and angular coordinates of the two-row periodic structure, which can be used for designing quasioptical attenuators.

A small‐size semilumped three‐port tunable power divider

AbstractIn this paper, a small‐size semi‐lumped three‐port power divider with both power and frequency tune is designed and measured. The proposed topology uses complex impedance transformers in each output branch. A 3D CPW prototype is realized with varactor diodes. It exhibits a wide tunable power, from −1.3 to −17 dB, and a wide working frequency tune, from 0.8 to 1.4 GHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 90–94, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22029