Unequal Power Divider Research Articles

Design and realization of 4 way Chebyshev Wilkinson power divider at 3 GHz frequency for 3 dimensional radar application

In the radar system, detection of objects with high accuracy is needed. Therefore, a low sidelobe antenna is needed to avoid interference from other detected targets. One method to suppress sidelobe antenna is by using unequal power divider with Chebyshev polynomial excitation coefficients. In this paper, we will discuss about the design and fabrication of Chebyshev Wilkinson power divider for 3 dimensional radar application. This research was conducted through 4 stages, namely design, simulation, fabrication and measurement. This power divider is realized in the form of a microstrip using Rogers R0-4003C (lossy) substrate with a thickness of 1,524 mm and a dielectric constant of 3.55. The simulation and measurement results are met the desired specifications, the operating frequency is at 3 GHz with a bandwidth of 200 MHz, the return loss is less than -10 dB, the insertion loss value is in accordance with Chebyshev, the isolation value of the port is less than -10 dB, and the unbalance phase is smaller than 2.5°.

Multilayer Packaging SIW Three-Way Filtering Power Divider With Adjustable Power Division

A new three-way filtering power divider (FPD) design based on multilayer substrate integrated waveguide (SIW) with equal/unequal power division is proposed in this brief. By elaborately integrating three same-type slotline-microstrip transition structures with a pair of TE101-mode resonant cavities, dual-mode three-way filtering power division response is attained in the design. Owing to the loading effect of the common coupling slot, one transmission zero is generated to improve lower passband selectivity. Furthermore, three-way equal and unequal power division can be achieved by flexibly changing the length of the microstrip line beyond the coupling slot. Simultaneously, favorable in-band port-to-port isolation is obtained by loading isolation resistors between the three output microstrip lines. For demonstration, two FPD prototypes with different power division ratios (1:1:1 and 1:1:1.5) operating at 11.8 GHz are designed, fabricated, and tested. The measured results agree well with the simulation results, verifying the presented design concept.

Dual‐band Gysel power dividers with large frequency ratio and unequal power division

In this article, a dual-band Gysel power divider is proposed based on the topology of finite-ground microstrip line. The general design method for the large frequency ratio and unequal power division is derived and the detailed design rules are provided. It is shown that the frequency ratio can be achieved from 1 to 10, and the power division ratio of each frequency band can be separately determined. Moreover, the phase differences at two operating bands could be designed to be either in-phase or out-of-phase. Finally, two prototypes are designed, implemented, and experimented to validate this proposal. The measured results of the first design show the frequency ratio of 4 with power division ratios of 2:1 in both passband, while the second example is designed with the frequency ratio of 10 with power division ratios of 2:1 and 1:1 in the first and second passband, respectively. Both results show a good agreement between the simulated and measured results.

Dual‐band filtering power divider with unequal power division ratio and low‐loss characteristic

In this article, a dual-band filtering power divider with unequal power-division ability is proposed. Different from conventional equal power dividers constructed by filters or coupled resonators, noncoupled structures are employed in this design. As a result, low-loss characteristic is realized for the proposed power divider. In this proposed structure, the dual-band unequal power allocation is realized by replacing conventional single-band λ/4 transformers with dual-band ones (T-junction structures). Three identical λ/4 stepped impedance resonators are properly attached to all the three ports of the proposed power divider to generate an extra transmission zero between two operational bands. Therefore, a filter-like shaping in its S-parameter results is obtained. A resistor is located between two outputs for output isolation. Mathematical derivations of the overall design procedure are also provided based on the circuit models and transmission line theory. Meanwhile, a resistor for output isolation is also included between two outputs, whose value can be calculated using given equations. For validation, a prototype operating at 0.9 and 2.1 GHz are designed, fabricated, and measured. The isolations between two outputs are 30 and 26 dB while the phase differences are only 2.5°and 4.9° at 0.9 and 2.1 GHz in the measurement, indicating good consistence of outputs. Measured |S21| and |S31| are −(1.76 + 0.3) dB, −(4.77 + 0.2) dB at 0.9 GHz and −(1.76 + 0.6) dB, −(4.77 + 0.5) dB at 2.1 GHz.

N-Way Compact Ultrawide Band Equal and Unequal Split Tapered Transmission Lines Wilkinson Power Divider

In this article compact N-way Ultra Wide Band (UWB) equal and unequal split Wilkinson Power Divider (WPD) using exponentially I»/4 Tapered Transmission Line Transformers (TTLTs)is designed and simulated. First 2-way WPDs are designed and simulated and then cascaded to get 4-way, 6-way equal and unequal split UWB WPDs in addition to 8-way equal split UWB WPD. The simulated results of all the designed dividers are good in terms of insertion, return losses and group delay through UWB frequency band. The analysis of these dividers is carried out using the commercial ANSYS High Frequency Structure Simulator (HFSS) software package which based on Finite Element Method (FEM). Moreover, A MATLAB built-in function “fmincon.m” is used to find the optimum values of the three resistors chosen for perfect isolation

The Unequal Wilkinson Power Divider 2:1 for WLAN Application

A power divider is a three-port microwave device that is used for power division or power combining. They are reciprocal devices, i.e. they can also be used to combine the power from output ports into the input port. The power dividers are widely used in microwave circuit designs. Indeed, this paper describes the design and simulation of 2:1 power divider at 3.6 GHz (802.11y) frequency for Wireless Local Area Network (WLAN) applications using Advanced Design System software (ADS). This device provides maximum isolation among three ports. It is highly advantageous for limited bandwidth applications. The Wilkinson Power Divider can also be manufactured with distribution of unequal powers.Therefore, in this article a conception of a Wilkinson unequal Power Divider is presented and our interest is a ratio of 2:1 at central frequency of about 3.6 GHz.

High Gain UWB Four Elements Antenna Array for C-Band and X-Band Application

The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by International Telecommunication Union. The X-band is used for terrestrial broadband communication, radar applications, and portions of the X-band are assigned for deep space telecommunications. In this paper, a design of 4 × 1 Ultra Wide Band (UWB) antenna array for C-band and X-band applications is introduced. Metamaterial sixteen-unit cells are incorporated into each antenna element for radiation characteristics enhancement purposes. Permeability and permittivity of metamaterial unit cells are obtained all over the operating bandwidth. UWB unequal power divider is used to feed the proposed four elements antenna array based on Chebyshev excitation method. The proposed antenna has a suitable 3 dB beam width and gains all over the operating bandwidth which extends from 5.6 GHz to 10.9 GHz. The proposed antenna covers 60% and 72.5% of the C-band and X-band, respectively. The proposed antenna is fabricated, measured, and good agreement is obtained between simulated and measured results. The obtained performance ensures the suitability of the proposed antenna array for C-band and X-band applications.

Balanced Rat-Race Couplers With Wideband Common-Mode Suppression

In this article, various types of six-port balanced rat-race couplers with wideband common-mode suppression characteristics are presented. In these couplers, the input and output ports can functionalize either as single-ended or differential terminals to realize different operational modes. The power-splitting ratio for these balanced couplers can be flexibly adjusted by means of the values of the characteristic-impedance parameters of their constituent transmission-line segments. Furthermore, the employment of double-sided-parallel-strip-line-(DSPSL)-based 180° phase inverters instead of half-wavelength transmission-line-based ones allows for the considerable enlargement of their operation bandwidth in more-compact circuits with lower in-band insertion-loss levels. For experimental-validation purposes, two microstrip prototypes at $f_{0}=0.9$ GHz with equal and unequal power division are fabricated and characterized. They exhibit common-mode rejection levels higher than 15 dB from 0 to 1.8 GHz (i.e., 0– $2f_{0}$ ) and differential-to-common- mode-conversion suppression levels above 15 dB within the spectral range 0–1.49 GHz (i.e., 0– $1.65f_{0}$ ).

A Miniaturized Dual-Band Dual-Polarized Band-Notched Slot Antenna Array With High Isolation for Base Station Applications

In this article, a miniaturized dual-band dual-polarized slot antenna array is proposed for base station applications. It consists of two closely located $1 \times 4$ subarrays for the digital cellular system (DCS) and wideband code division multiple access (WCDMA) operations. The band-notched slot antenna (BNSA) is designed and adopted as the subarray element with radiation-suppression characteristic at notch frequencies. The notch frequency for one subarray is designed at the center operating frequency of the other subarray. As a result, the radiation from DCS subarray could be effectively suppressed within the WCDMA band and vice versa, resulting in high isolation between two subarrays with a small separation distance. By using the artificial magnetic conductor (AMC) reflector, the array height could be reduced by half, as compared with the perfect electric conductor (PEC) counterpart. In addition, a four-way unequal power divider is designed for the array's beam-pattern synthesis. For the demonstration, the proposed array is fabricated and measured. The measurement results show that the dual-band array achieves the impedance bandwidths of 1.65-1.88 and 1.89-2.22 GHz, the isolations over 25 dB, the realized boresight gains of 12.2-12.8 and 12.3-13.2 dBi, and the sidelobe levels below -18 dB. The results indicate that the proposed array is a promising candidate for base-station applications.

Synthesizing Uniform Amplitude Sparse Dipole Arrays With Shaped Patterns by Joint Optimization of Element Positions, Rotations and Phases

This paper presents a novel method for synthesizing sparse dipole arrays with shaped patterns by joint optimization of element positions, rotations and phases. Such joint optimization exploits maximum available degrees-of-freedom under the assumption of uniform amplitude excitations to improve the shaped power pattern synthesis performance, and it leads to a reduced number of elements and simpler feeding network without using unequal power dividers for the array. The copolarization (COP) and cross-polarization patterns for a rotated dipole array are derived in a 2-D case, and then the vectorial shaped pattern synthesis problem is formulated as finding the optimal solution by maximally approaching the desired COP pattern shape under multiple constraints on the sidelobe level (SLL) and cross-polarization level (XPL). In addition, an asymmetric mapping method is incorporated into the proposed joint optimization, so that the minimum element spacing constraint can be also used for the synthesis of planar sparse dipole arrays. The comprehensive learning particle swarm optimization (CLPSO) algorithm is adopted to optimize the element positions, rotation angles and phases. A set of synthesis experiments including linear and planar rotated dipole arrays with a different pattern shape requirements are conducted to validate the effectiveness and robustness of the proposed approach. Synthesis results show that the proposed approach can save about 17.24% – 55.86% elements as well as many unequal power dividers for test cases.

A Flexible Quadrature Coupler With Reconfigurable Frequency and Coupling Ratio in Switchable Coupling Direction

A highly reconfigurable and switchable quadrature coupler with simultaneous control in terms of operating frequency, coupling ratio, and coupling direction is presented. To start with, a prototype coupler based on an ideal admittance-inverter model is investigated, and a method to obtain the admittance-inverter values for an arbitrary coupling ratio is described. Next, a tunable-admittance-inverter network implemented with lumped inductors and varactors, which features reconfigurable operating frequency, and tunable-admittance-inverter value is discussed. The conceived reconfigurable coupler is then realized by replacing the ideal admittance inverters with the proposed tunable-admittance-inverter circuit to provide it with operating-frequency and coupling-ratio controllability. Furthermore, when exchanging the admittance-inverter values in the coupler, the coupling direction is switched from forward to backward. The proposed technique is further developed into a general design procedure for reconfigurable-coupler implementations with an arbitrary admittance-inverter-based network. Wilkinson power dividers with equal and unequal power-division ratios are also shown as examples. For experimental/demonstration purposes, a reconfigurable coupler prototype is fabricated and characterized. It demonstrates a tunable operating frequency from 1 to 1.5 GHz, a controllable power-division ratio between output ports from 1 to 0.7, and switchable operational direction between forward and backward.

Planar circularly polarized X‐band array antenna with low sidelobe and high aperture efficiency for small satellites

A planar broadband circularly polarized (CP) X-band array antenna with low sidelobe and high aperture efficiency is presented for small satellite applications. The array design is composed of 4 × 4 broadband CP stacked patch elements, which are fed by a feeding network consisted of unequal series-parallel power dividers to achieve the low sidelobe and high aperture efficiency. The final prototype with overall size of 100 mm × 100 mm × 3 mm (2.73λ0 × 2.73λ0 × 0.082λ0 at 8.2 GHz) was fabricated and measured. The antenna has a broadband characteristic with |S11| < −10 dB bandwidth of 15.9% (7.52-8.82 GHz) and 3-dB axial ratio bandwidth of 11.95% (7.63-8.60 GHz). Also, it achieves an excellent broadside CP radiation with a gain of 17.2-20.03 dBic, a sidelobe level of <−20 dB, and aperture efficiency of 65% to 97.5%. With these features, the proposed antenna is a good candidate for high-speed data downlink onboard small satellites (MiniSat, MicroSat, NanoSat, and CubeSat).

Comments on “A Dual-Band Port-Extended Branch-Line Coupler and Mitigation of the Band-Ratio and Power Division Limitations”

In the above paper ( IEEE Trans. Compon., Packag., Manuf. Technol., vol. 7, no. 8, pp. 1313–1323, Aug. 2017), Maktoomi et al. proposed a dual-band unequal power division branch-line coupler with four arbitrary terminated resistances using the dual-band impedance matching networks and core coupler with equal complex port impedances. However, the definition of transmission phase delay of matching networks provided by authors is incorrect. In this paper, the definition of transmission phase delay of matching networks is clarified.

Comments on “A Continuously Tunable Unequal Power Divider With Wide Tuning Range of Dividing Ratio”

The power-dividing ratio analysis by Ye et al. is based on an inadequate equivalent circuit and neglects the effect of the isolation resistor. It is shown that the isolation resistor should be included for the power-dividing analysis and the exact analysis results are presented for the power-dividing ratio. According to the exact analysis, the wide tuning range of the power division ratio claimed by Ye et al. is sharply reduced including the effect of the isolation resistor.

GD analysis of arbitrary terminated PD with an unequal power‐dividing ratio

This study presents the group delay (GD) analysis of an arbitrary terminated unequal power-dividing ratio of a power divider (PD) combined with a negative group delay (NGD) circuit. The proposed circuit can provide an arbitrary prescribed positive group delay (PGD) between ports 2 and 1, whereas it can provide NGD between ports 3 and 1. From analytical analysis, it is found that the magnitude and GD of the PGD path depend only on the power-division ratio, whereas the magnitude and GD of the NGD path depend on the power-division ratio as well as the on NGD circuit. For an experimental verification, the arbitrary terminated unequal PD was designed, fabricated, and measured at the centre frequency of 2.14 GHz. The measurement results are in good agreement with the simulation and predicted theoretical results. For the NGD bandwidth and magnitude flatness enhancement, coupled-line NGD circuits with slightly different centre frequencies connected in parallel were designed and fabricated providing wider bandwidth than the single stage and showed a practical applicability.

Implementation and experimental verifications of microstrip antennas for angular scanning of a Doppler radar

The aim of this study is to improve operational capabilities and range of the MIT-Coffee Can Doppler radar via aperture coupled Vivaldi type transmitter antenna, patch array receiver antenna, and an unequal power divider. Accordingly, a mechanical angular scanning feature for tracking multi-targets and the system integration of lightweight microstrip structures are realized for the radar. A narrow beamwidth in the receiver and a well impedance matching on the overall system to reduce return losses are achieved for the considered application. Good agreements between simulations and measurements for the fabricated antennas/divider and a successful integration of the antennas to the existing system for finding a moving target angular location is reported. It is shown that through wall identification and target velocity at scanned regions can be obtained with the proposed hardware configuration. Simulation results of antenna parameters for various number of array elements are listed which could be a useful tool for different engineering applications.

A Matched Negative Group Delay Circuit and its Integration With an Unequal Power Divider

A Matched Negative Group Delay Circuit and its Integration With an Unequal Power Divider

An unequal dual-band power divider with composite left/right-handed transmission lines

An unequal dual-band power divider with composite left/right-handed transmission lines

Equal and unequal quad‐band Gysel power dividers

This article presents for the first time a quad-band Gysel power divider capable of achieving equal and unequal power division at four arbitrary frequencies. The structure of the proposed divider is similar to its single-band counterpart but loaded with quad-band reactive networks. The design procedure and theoretical analysis of the proposed divider are presented. A quad-band Gysel power divider with equal division and another with 2:1 unequal division are designed at the operational frequencies of 0.85, 1.6, 2.4, and 3 GHz. Simulation and measurement results of the two dividers are presented, and good performance is observed at each band. For both designs, the realized power division ratios are within 1 dB from their ideal values, whereas the matching and isolation levels are below −10 dB at the four bands.

Compact unequal filtering power divider operating in two bands with controllable characteristic impedances

AbstractA design method for unequal filtering power dividers (PDs) working at 2 bands is presented in this article. Compared with conventional unequal PDs, in this method, each section of the proposed circuit uses transmission lines whose characteristic impedances are controllable to avoid high‐impedance line. Meanwhile, the conventional λ/4 transmission line in PDs is substituted with a pair of proper dual‐mode resonators. To prove the effectiveness of the proposed design principle, a miniaturized unequal filtering PD working at 3.5 and 4.9 GHz is designed, fabricated and measured. Eventually, it is clear that the simulated results and the measurements have favorable agreement.