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In this paper, a new approach for designing a planar high frequency selectivity filtering coupler based on a circular patch resonator is proposed. In order to explain the operating principle, the resonant property of the circular patch resonator has been investigated firstly. Two circular patch resonators connected by two microstrip lines are used in this design. A filtering coupler is achieved by adjusting the feeder position and the length and width of the microstrip line used to connect the two resonators. Without additional circuits, the desired 0° and 180° phase differences are realized by the inherent in-phase and out-of-phase characteristics of E-fields at the TM11 mode. To improve the passband selectivity, transmission zeros are created by introducing a coupling between the source and load through the coupling slots etched on the ground. Finally, a prototype of the filtering coupler centered at 2.12 GHz is designed, implemented, and tested, while the measured results coincide well with simulated ones, verifying the proposed design concept. [ABSTRACT FROM AUTHOR]

In this article, a reconfigurable phase shifter loaded two PIN diodes is presented. Compared with the traditional phase shifters, the proposed phase shifter can achieve two phase shifts in one single phase shifter by controlling the PIN diodes, which make it more superior in the feeding network's application of array antennas. Moreover, this phase shifter can widen the bandwidth, decrease the size and realize a wider phase shift range in a simple structure. For simplifying the process of this design, this article introduces a simply method to design the configurable phase shifter. To confirm the presented design, the proposed phase shifter is fabricated and measured. A good agreement between the measured and simulated results can be observed. [ABSTRACT FROM AUTHOR]

A reconfigurable balanced phase shifter is designed in this paper, which can achieve stable differential mode (DM) phase shift and high common mode (CM) suppression. The proposed balanced phase shifter is mainly composed of micro strip/slot line transition structure and π‐shape slot line. The U‐shaped micro strip line and the stepped impedance slot line are employed to form the differential input and output ports, which can make the DM response and the CM one are independent. By switching the PIN diode on or off, a stable 180° DM phase shift difference is achieved between two states. In order to verify the design, a 180° balanced phase shifter with a central frequency of 4.7 GHz was simulated and fabricated. DM insertion loss of the design is 1.1 dB, DM phase deviation range is ±5°, 10 dB DM impedance matching fractional bandwidth is 45%, and phase fractional deviation bandwidth is 42%. Meanwhile, the CM rejection can reach about 35 dB. The simulation and measurement are in good agreement with the theory. [ABSTRACT FROM AUTHOR]

In this article, a balanced filtering antenna array with quasi‐Yagi performance is presented. The proposed design is composed of a balanced‐to‐single‐ended power division network, two bandpass filtering units and a linear quasi‐Yagi array including four elements. A steep differential‐mode (DM) passband frequency response is obtained by introducing the triple‐mode folded cross stub‐loaded resonators (FC‐SLRs) in the power division network. The fractional bandwidth and center frequency can be controlled conveniently by adjusting the dimensions of FC‐SLRs. Further, the design procedure is simplified due to the DM responses which are independent of the common‐mode (CM) ones. The proposed antenna array with high gains, good CM rejections, and low cross‐polarization levels is achieved. In addition, three radiation nulls are engendered on the sidebands to improve the selectivity. For demonstrating its feasibility, the balanced antenna prototype is fabricated and measured. The good performances of the proposed balanced filtering antenna array are observed. [ABSTRACT FROM AUTHOR]

In this paper, a quint‐mode slotline resonator (QMSR) is analyzed and designed. The proposed resonator has similar performances to those of the conventional microstrip multimode resonator, while it is located at the bottom ground layer. To the best of our knowledge, this is the first time that QMSR is proposed. By properly adjusting the dimensions of the proposed QMSR, quasi‐independent control of the five resonant frequencies is realized, thereby an ultrawideband (UWB) differential‐mode (DM) transmission passband can be obtained. By employing balanced microstrip/slotline transition structure, a high and wideband common‐mode (CM) suppression can also be realized, which is independent of the DM responses. Thereby, only the DM performances need to be considered, which simplify the design procedure greatly. In addition, one notched band is achieved to suppress the special electromagnetic interference. To validate the design concept, one prototype circuit of the proposed balanced UWB bandpass filter is implemented following the given design procedure. Good agreement between the measurement and simulation results can be observed. [ABSTRACT FROM AUTHOR]

In this article, a new subwavelength element is introduced into the broadband folded reflectarray antenna (FRA). The element comprises a rectangular split‐ring resonator with two slits and a square patch located in the center of the rectangular ring. It can achieve superior cross polarization conversion (CPC) performance from 16.2 to 26.4 GHz with 1 dB bandwidth of 45.4%, and high orthogonal polarization isolation. Furthermore, changing the positions of two splits of the element can achieve two discrete reflection phases (0° and 180°) with the high CPC efficiency and angular stability. To verify the feasibility, an FRA using the digitally quantized phase distribution method is designed and measured at 22 GHz. The measured results show that the 1 dB gain bandwidth of the proposed FRA is 30.8%, and the maximum aperture efficiency is 15.4%. This superior performance is comparable with the existing FRAs. [ABSTRACT FROM AUTHOR]

A balanced wideband bandpass filter (BPF) with a high frequency selectivity, controllable bandwidth, and good common‐mode (CM) suppression based on nested split‐ring resonators (SRRs) is proposed in this article. The proposed nested SRRs are applied to form three transmission poles (TPs) that can achieve a wide differential‐mode (DM) passband centered at 3.0 GHz. Meanwhile, two transmission zeros (TZs) are generated to realize a high frequency selectivity of the DM passband. Moreover, TPs and TZs can be quasi‐independently controlled by changing the physical lengths of SRRs and the gaps between them, which can greatly improve the flexibility and practicality of the design. The proposed balanced BPF is fed by balanced microstrip‐slotline (BMS) transition structures. For the CM signals, the BMS transition structures can achieve a good wideband CM suppression without affecting the DM ones, thereby simplifying the design procedure. In order to validate its practicability, a balanced wideband BPF is fabricated and a good agreement between the simulated and measured results is obtained. [ABSTRACT FROM AUTHOR]