Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

This paper presents a novel method for designing Gysel power dividers with arbitrary power-division ratios as well as filtering responses. A coupling structure is utilized to replace the quarter-wavelength microstrip line in the power divider. By altering the coupling strength, the power ratio can be arbitrarily controlled with the highest ratio of 10:1. Furthermore, the coupling structures enable the filtering function of the power divider. Two transmission zeros are created near the passband edges, resulting in high-selectivity quasi-elliptic responses. Theoretical analysis is carried out, and closed-form equations are derived based on circuit theory and transmission line theory. For demonstration, three filtering Gysel power dividers are implemented with different power-division ratios (1:1, 3:1, and 10:1). In all of these circuits, power splitting and bandpass filtering functions are observed with good performance. Comparisons of the measured and simulated results are presented to verify the theoretical predications.

Gysel Power Divider With Arbitrary Power Ratios and Filtering Responses Using Coupling Structure

A compact broadband Gysel power divider with arbitrary power-dividing ratio is proposed. This divider is derived from the conventional Gysel power divider by substituting an ideal phase inverter for the 180° phase shifter, which significantly improves the bandwidth and reduces the circumference to 1 λg evaluated at the center frequency. A wide range of power-dividing ratio (1-6.25) is supported by changing the impedance ratio of the transmission lines, while the dual-band impedance matching characteristic with frequency ratio (1-2.9) is obtained only by varying the impedances of the transmission lines (20-135 Ω). Closed-form equations are derived for design parameters. The ideal phase inverter is realized by two transitions: microstrip-to-slotline and slotline-to-microstrip transitions. By utilizing this phase inverter, two microstrip Gysel dividers with power-dividing ratios of 1:1 and 2:1 and operating at 1.5/2.5 and 1/2 GHz, respectively, are designed, fabricated, and measured. The measured results are in good agreement with the simulated ones. The first measured results show a bandwidth of 80% with better than 15-dB return loss and 29-dB isolation from 1.19 to 2.76 GHz. The second measured results show a bandwidth of 95.8% with better than 12-dB return loss and 24-dB isolation from 0.8 to 2.27 GHz. To the authors' knowledge, the most wideband Gysel power divider using microstrip technology is proposed for the first time.

Compact Broadband Gysel Power Divider With Arbitrary Power-Dividing Ratio Using Microstrip/Slotline Phase Inverter

This paper proposes a novel modified Wilkinson power divider with wide isolation bandwidth The isolation bandwidth can be extended by an additional isolation network (INW) in the circuits An equal and an unequal 4-GHz modified Wilkinson power divider on FR4 with compact circuit sizes are designed and measured to verify the new design concept The measurement results show the operation bandwidth from 18 to 64 GHz with 20-dB isolation in the equal case In the unequal case, the operation frequency starts from 24 to 53 GHz with 20-dB isolation Moreover, a 3-GHz 1-to-3 modified Wilkinson power divider is realized with the operation frequency from 205 to 383 GHz with 20-dB isolation These circuits demonstrate that the isolation bandwidth can be extended by an INW, and this INW can be used in many power dividers with different applications To the authors' knowledge, these circuits provide the widest fractional bandwidth of isolation in a Wilkinson power divider ever reported, except those using multisection structures

A Modified Wilkinson Power Divider With Isolation Bandwidth Improvement

In this paper, a balanced-to-balanced power divider is proposed, for the first time, with arbitrary power division, which can be regarded as the balanced form of a Gysel power divider. The constraint rules are provided for its mixed-mode and single-ended S-parameters. The six-port network is analyzed by simplifying it to two-port networks with other ports matched at the central frequency. Its critical characteristic impedances are then calculated analytically by our derived equations according to the desired differential-mode power division ratio. The maximum achievable power division ratio is 1:4.692 when the characteristic impedances are limited within the realizable range of 20-120 Ω. The impacts of several freely selected design parameters on the operating bandwidth are explored numerically. A prototype is realized by microstrip lines and lumped resistors with the power division ratio of 1:32. The balanced-to-balanced performances of unequal power division, low differential-mode insertion loss, good suppression of common-mode noises, and mode conventions have been demonstrated by the simulated and measured results of the balanced-to-balanced power divider prototype.

A Balanced-to-Balanced Power Divider With Arbitrary Power Division

This paper presents an exact closed-form design method for dual-band unequal Gysel power divider with arbitrary termination resistance. To obtain the unequal property, branch lines with different characteristic impedances attached to a short-circuit terminated stub and an open-circuit terminated stub are needed. Arbitrary termination resistance matching can be achieved without additional output transformers. Line impedance analysis shows the proposed structure can support large power-dividing ratio (up to 6) with wide frequency ratio range (1.5-2.4). Power operation analysis shows that it maintains Gysel divider's high power-handling advantage over Wilkinson divider.

Design of Unequal Dual-Band Gysel Power Divider With Arbitrary Termination Resistance

This paper presents a modifled Gysel power divider (PD) with harmonic suppression performance by utilizing equivalent ƒ- shaped, T-shaped and ƒ-T-hybrid-shaped open stubs transmission line (TL) models. Explicit closed-form expressions for generating parameters of the equivalent TL models are derived based on the ABCD matrix analysis. The proposed PD not only features suppression at the hoped harmonic frequencies and ∞exible layout, but also maintains Gysel PD's high power handling advantage. For demonstration, the simulated and experimental results of three proposed PDs at 1GHz implemented on microstrip are given.

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Modified Gysel Power Divider with Harmonic Supperssion Performance

This paper presents a parallel-circuit Class-E amplifier that maintains it operating characteristics even when the output capacitance of the transistor is greater than the optimum shunt capacitance. The finite dc feed inductor in the parallel circuit topology is replaced by a transmission-line compensation circuit to eliminate the limitations on the operating frequency imposed by the output capacitance. Theoretical formulas for the circuit elements of the proposed network are derived in detail, and the analysis is validated by simulation and measurement. The measured maximum output power of 40.1 dBm, drain efficiency of 77.5%, and power-added efficiency of 70.8% were obtained at 2.8 GHz with a 29.4-dBm input power. These measurements show a similar or better level of efficiency and output power that is reported for other amplifiers at lower frequencies using the same transistor.

An Extended Topology of Parallel-Circuit Class-E Power Amplifier Using Transmission-Line Compensation

The invention relates to a double-frequency power divider and a design method thereof. The double-frequency power divider comprises three ports, six branch transmission lines, a short circuit branch knot, an open circuit branch knot and two earthing isolating resistors. The double-frequency power divider provided by the invention can realize any double frequency, any power distribution ratio, power distribution and composition of any resistive load, and overcomes the defects that the traditional Gysel type power divider only can carry out odd-time frequency doubling operation, equipower distribution, and equal port load; the double-frequency power divider is simple and compact in double-frequency working, the design is simple, the adjustable ranges of transmission line characteristic resistance and the resistor value dynamic state of each isolating resistor are large, the standard resistor value is conveniently taken and the microstrip line process has a requirement of the transmission line characteristic resistance to be realized; and the double frequency characteristic is obtained, simultaneously, the high power application of the Gysel type traditional power divider is reserved, and the double-frequency power divider is particularly suitable for microwave double frequency and high power distribution composition application.

Double-frequency power divider and design method thereof

This paper presents a dual-band rat-race coupler with arbitrary power dividing ratio. The dual-band and unequal power dividing characteristics are obtained by using a dual-frequency 180 degree phase shifter with the conventional coupler. Closed-form design equations are derived. The proposed structure can support large power dividing ratio with a wide frequency ratio range. The measured results show that good matching, isolation, power transmission and phase balance can be achieved at two operating frequency bands.

Yuepeng Yan

Papers

Design of Unequal Dual-Band Gysel Power Divider With Arbitrary Termination Resistance

Modified Gysel Power Divider with Harmonic Supperssion Performance

An Extended Topology of Parallel-Circuit Class-E Power Amplifier Using Transmission-Line Compensation

Double-frequency power divider and design method thereof

Unequal Dual-Band Rat-Race Coupler based on Dual-Frequency 180 Degree Phase Shifter