Maoyu Fan

Compact Dual-Band Gysel Power Divider Based on Composite Right- and Left-Handed Transmission Lines

A novel compact dual-band Gysel power divider with controllable frequency ratio using fully integrated composite right/left-handed (CRLH) transmission lines (TL) is presented in this letter. The Π-shaped CRLH TLs are utilized to realize the dual-band response. Theoretical analysis indicates that the frequency ratio can be controlled by changing the element values and the number of the constructing cells of the CRLH TLs. In addition, the proposed structure is compact. For demonstration, a dual-band Gysel power divider operating at 2.4 and 3.5 GHz, respectively, is implemented. Measured results show that good impedance matching, isolation, and power transmission can be satisfied at the dual passband simultaneously.

Compact Bandpass-Filtering Response Power Dividers with High Isolation and High Frequency Selectivity

ABSTRACT A compact power divider integrated filtering response with high isolation and high frequency selectivity is presented in this article. The four short-circuited-loaded quarter-wavelength resonators are employed to construct the presented compact power divider. The presented divider can be viewed as an integration of a second-order dual-mode bandpass filter and the quasi-Wilkinson power divider. In order to improve the frequency selectivity of passband, the cross-coupling circuits between input port and output ports are used. A power divider with bandpass-filtering response is designed, fabricated, and measured. The operating central frequency of the fabricated power divider is at 2.43 GHz. The measured 3-dB insertion loss bandwidth is about 180 MHz and the measured minimum insertion loss is about 0.85 dB. The measured isolation between the output ports is around 30 dB.

Compact Multiple-Way Power-Dividing Network with Bandpass-Filtering Response Using Spiral Resonators

ABSTRACT A new type of multiple-way out-of-phase power-dividing network with bandpass-filtering response using spiral resonators is proposed. The basic structure unit is a compact two-way out-of-phase power divider with bandpass-filtering response. The introduction of two identical spiral-type resonators can generate transmission zeros in the lower or upper stopband to implement the bandpass-filtering function. Impedance matching and out-of-phase performance are analyzed by using the even- and odd-mode method based on four-port network theory. A four-way out-of-phase power-dividing network with bandpass-filtering response is constructed and designed according to the basic two-way out-of-phase power-dividing structure. The simulated and measured results of the fabricated out-of-phase bandpass-filtering power-dividing network demonstrate the reasonable performance of impedance matching, amplitude balance, and bandpass-filtering function.

Compact Triple-Band Power Divider Integrated Bandpass-Filtering Response Using Short-Circuited SIRs

Based on short-circuited stepped-impedance resonators (SIRs), a triple-band power divider (PD) with bandpass-filtering response is presented. The triple-passband filtering response is achieved for the presented PD. The first and third passbands are realized by the short-circuited SIRs, while the second passband is introduced and tuned by half-wavelength resonators independently. The triple-passband response of the presented PD has been designed by using the coupling matrix synthesis. Moreover, the desired resonant frequencies of the three passbands can be obtained by tuning the impedance ratio and electric lengths of the high-impedance and the low-impedance transmission lines. The performance of the PD is verified by the simulation and measurement results.

Novel Four-Way Slotted-Substrate Integrated Waveguide Power Divider Using Identical Coupling Circuits

ABSTRACT A novel four-way X-band slotted-substrate integrated waveguide (SIW) power divider using an identical slot-coupling structure has been proposed in this article. The proposed power divider was realized by using an identical transition between a resonant slotted SIW and output microstrip lines, and four identical rectangular coupling slots were employed to achieve good impedance matching and equal signal transmission. The proposed power divider is designed, fabricated, and measured. The measured results show a reasonable agreement with the simulated ones and the advantages of its low profile, efficient heat sinking, as well as its potential for high power-combining efficiency.

Four-way wideband power divider using a hybrid HMSIW/microstrip line

ABSTRACT A four-way wideband power divider using hybrid HMSIW and a microstrip line is presented. The input signal through the Wilkinson power divider is, respectively, fed into two wideband HMSIW power dividers to achieve a four-way power divider. Two multimode SIR resonators are loaded at both sides of the input microstrip line to improve the frequency selectivity. The resistive slot on the bottom layer is employed to obtain good output isolation without an increase in circuit size. This four-way power divider is designed, fabricated, and measured. The measured 10 dB return loss range from 3.8 to 6.14 GHz (fractional bandwidth of 47.1%), and the suppression of upper stopband is greater than 16 dB from 6.7 to 9 GHz. All measured results show reasonable agreement with the simulated ones.

A bionic algorithm based synthesis of shaped reflector for a terahertz quasi-optical power combiner

A relative efficient procedure with a bionic algorithm is proposed, which combines a real-coded genetic algorithm and a differential operator, to synthesis a shaped reflector surface for terahertz quasi-optical power combiner. The combiner consists of a linear array of five rectangular horns, a binary phase grating as a hologram, a shaped reflector, and a receiving horn antenna. The hologram transforms the beams of the antennas into a pseudoplane wave. The transformed wave is coupled into a rectangular output horn antenna by a parabolic reflector. The final field distribution on the receiving plane can be obtained by using a bionics algorithm to optimize the mirror surface relief. The power combiner operating at 300GHz is described corresponding of 62.5% theoretical power combining efficiency.

Compact half-mode SIW bandpass filter with high-frequency selectivity

ABSTRACT This article presents a compact bandpass filter (BPF) using half-mode substrate integrated waveguide technology. The source-load cross-coupling structure has been used in the BPF and the transmission zeroes have been generated to improve the frequency selectivity. The proposed filter is smaller than its conventional substrate integrated waveguide counterpart with similar filter specifications and has advantages of high-frequency selectivity and miniaturization. The measured results show that the designs can provide 170 MHz bandwidth at 3.5 GHz with a return loss of 15.1 dB and an insertion loss of 2.1 dB.

Compact Quad-Band Bandpass Filter Using Quad-Mode Stepped Impedance Resonator and Multiple Coupling Circuits

A compact quad-band bandpass filter using quad-mode stepped impedance resonator (QMSIR) is investigated in this paper. To get suitable coupling within the four passbands, the multiple coupling circuits between the input/output ports and QMSIR are applied. Based on the symmetry of the QMSIR, even- and odd-mode theory is used to analyze the equivalent circuits of the QMSIR. Design equations are derived, and they are used to guide the design of the circuits. Four passbands can be easily tuned by its physical dimensions. Upper stopband is improved by adding the open-loop SIRs at both I/O ports. Transmission zeros among each passbands are generated, resulting in high isolation and frequency selectivity. An experimental circuit is fabricated and evaluated to validate the design concept. The measurement results are in good agreement with the full-wave simulation results.

Compact Broadband Bandstop Filter Based on Composite Right/Left Handed Transmission Line

ABSTRACT A compact broadband composite right/left handed transmission line (CRLH-TL) bandstop filter based on a triple path signal interference mechanism is presented. The filter incorporates CRLH-TLs, conventional transmission line, and the slotline to implement a compact design. The CRLH-TL is used to realize negative phase shift. The meandered slotline is etched on the ground plane below the interdigital capacitor, which can improve both the in-band and out-of-band performance. The proposed filter avoids the 270/360 degree transmission line in conventional signal interference designs. The equivalent-circuit method is employed to analyze the presented bandstop filter. A broadband bandstop filter centered at 2.45 GHz is designed and fabricated. Good performance is obtained in the stopband as well as in the passband. Calculated, simulated, and measured results show good agreements with each other. The total size of the fabricated bandstop filter is 0.21λg × 0.11λg.