This paper presents a novel and simple design approach of multiport power divider with arbitrary power splitting ratio as well as filtering response. The relationship between the external Q -factors ( Q es) and power splitting ratio is theoretically analyzed, and it is found that the power allocation for the multiple outputs is determined by their Q e's ratio. By altering the Q es of the splitting ports, the power ratio can be arbitrarily controlled while the output total Q e is equal to the input Q e. Based on this, the two functions of power division and bandpass response of the proposed filtering divider can be designed independently. Accordingly, two practical three-way filtering power dividers with different division ratios (1:1:1 and 3:1:1) using the same topology based on the dielectric resonator (DR) are constructed for the first time. Both of them can be easily built by properly changing the lengths of feeding probes for the output DR without increasing the circuit size, while the phase difference between the splitting ports mainly depends on the direction of the feeding probes. To verify the proposed design concept, the two filtering power dividers with different division ratios mentioned above are implemented and measured. Comparisons of the measured and simulated results show good accordance and verify the theoretical predications.

Theory and Experiment of Multiport Filtering Power Divider With Arbitrary Division Ratio Based on Dielectric Resonator

This work presents a novel planar branch-line coupler topology developed for dual-band operation using an E-shaped impedance transformer network to supplant the conventional microstrip line. Explicit closed-form design equations for dual-band operation are derived using the ABCD matrices. The studied coupler features a large dual-band frequency ratio with a compact size. A prototype coupler centered at 1 and 8 GHz is first presented and experimentally examined to demonstrate the large frequency ratio. Further, another prototype coupler centered at 2.4 and 5.2 GHz for potential WLAN applications is also developed and experimentally characterized. Measurements and simulations for both prototype couplers show good performance within the studied dual-band frequencies.

/pdf/planar-dual-band-branch-line-coupler-with-large-frequency-1ta6f7m7xw.pdf

Planar Dual-Band Branch-Line Coupler With Large Frequency Ratio

Many Global Positioning System (GPS) services have been recently introduced that extend over a wide frequency range from 1.16 to 1.61 GHz. For reception, either a wideband or multiband receiver is required, which is typically challenging to design as it requires a wideband feed network and a wideband circularly polarized antenna. Here, we investigate a high-performance Global Navigation Satellite Systems (GNSS) patch antenna fed by a wideband feed network to provide circular polarization (CP) over the whole bandwidth. The feed of the developed CP patch antenna requires 0°, 90°, 180°, and 270° sequential phase shift; an improved feed network with ±8° phase imbalance is designed to be used in the circularly polarized antenna. The manufactured antenna demonstrated a return loss better than 10 dB, axial ratio 4.8 dB over the entire GNSS band. The developed antenna was connected to a GNSS receiver which tracked up to 28 satellites and the C/N 0 of the received GNSS signals was better than 50 dB. Such a high-performance antenna design targets precise localization market.

Toward High-Performance Wideband GNSS Antennas-Design Tradeoffs and Development of Wideband Feed Network Structure

This paper presents a universal design approach of multiport filtering power divider with the arbitrary power-division ratio, which is applicable for the designs of the single-ended/balanced circuit or hybrid of them. The power allocation in a specified passband is fulfilled by relying on two key factors in building a filter, i.e., coupling coefficient and external $Q$ -factor ( $Q_{\mathrm {e}}$ ). After synthesis for the bandpass response, the total input/output $Q_{\mathrm {e}}$ and the total coupling coefficient at each power dividing level can be determined. Subsequently, according to the desired power-dividing ratio, the coupling coefficient between the two coupled resonators and $Q_{\mathrm {e}}$ of each output can be easily determined. Once the parameters for filtering response are fixed, the power allocation can be determined by $Q_{\mathrm {e}}$ without effect on the filtering response. Thus, the two functions of bandpass and power dividing can be designed independently, which provides tremendous freedom for the overall design with the arbitrary order of filtering and number of output ports. The proposed topology has several advantages, such as flexibility, cost efficiency, and simple design procedure, which would be a good candidate for multiple-path operation in the current and future MIMO systems.

/pdf/universal-design-approach-for-multiport-filtering-power-5g3841bfsv.pdf

Universal Design Approach for Multiport Filtering Power Divider

A general design for multi‐output ports planar Wilkinson power divider

A compact dual-band five-way Wilkinson power divider with good RF performance is presented. Two-section impedance transformers are utilised to obtain the dual-band function. To facilitate assembling the isolation resistors among outputs, a second layer is introduced. The proposed power divider works at 0.915 and 2.45 GHz with small phase and magnitude imbalances.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/el.2017.1423

Compact dual-band five-way Wilkinson power divider

Primary challenges of developing a branch-line balun lie in the output isolation and impedance matching. A two-order branch-line balun topology, featuring enhanced electric performance, is ...

Broadband branch-line balun with good isolation and impedance matching

This paper presents a dual-band rat-race hybrid with phase compensation at microwave frequencies. The proposed rat-race hybrid has good magnitude and improved phase responses. Stub-loaded transmiss...

Dual-band rat-race hybrid with phase compensation

A broadband circularly polarized metasurface antenna with low radar cross section (RCS) is proposed. Four metasurface elements are arranged orthogonally in a 2×2 array and fed with a 90° phase difference to achieve circular polarization radiation. Each metasurface element is a nonuniform subarray of 4×4 metallic patches. Attributed to the nonuniform property of the metasurface element, two characteristic modes with different resonant frequencies but with similar surface current distributions are formed. By optimizing the geometric parameters of the nonuniform element, the two modes are merged with each other, resulting in bandwidth (BW) broadening of the proposed antenna. Simulated and measured results show that the designed antenna has a −10 dB impedance BW of 49.60%, 3 dB axial ratio BW of 33.13%, and peak gain of 13.17 dBic. Moreover, the RCS reduction is higher than 6 dB in the entire operation frequency band. Additionally, the antenna has a low profile of 0.08λ (λ is the free-space wavelength at an operation frequency of 8.25 GHz).

Broadband Low-RCS Circularly Polarized Antenna Realized by Nonuniform Metasurface

In this paper, a complicated metasurface for radar cross section (RCS) reduction is proposed. The nonuniform metasurface elements occupy anisotropic property. The adjacent metasurface elements are arranged orthogonally. Therefore, the reflected waves form the adjacent elements will generate different phase for a linearly polarized incident wave. Based on the phase cancellation principle, a broadband RCS reduction are achieved. Simulated results show that the proposed nonuniform metasurface achieves 6 dB RCS reduction from 6.6 GHz to 24.1 GHz under normal incidence.

Si-Yu Yin

Papers

Compact dual-band five-way Wilkinson power divider

Broadband branch-line balun with good isolation and impedance matching

Dual-band rat-race hybrid with phase compensation

Broadband Low-RCS Circularly Polarized Antenna Realized by Nonuniform Metasurface

Broadband Radar Cross Section Reduction Realized by Complicated Metasurface