Compact Tunable Filtering Power Divider With Constant Absolute Bandwidth

Abstract

This paper presents a novel frequency-agile filtering power divider with constant absolute bandwidth and high selectivity. The proposed design utilizes four coupled resonators to obtain the two functions of power division and filtering. Synthesis of the filtering power divider is carried out and the design guidelines are given. Varactors are then loaded to the resonators to enable frequency tuning. By using capacitors as well as magnetic and electric coupling to obtain required external quality factors and coupling coefficients, a constant absolute bandwidth is maintained when tuning the frequency. To demonstrate the validity of the proposed design, a circuit was fabricated. Experimental results show that the operating frequency can be changed from 0.62 to 0.85 GHz with the 3-dB absolute bandwidth of 60 2.5 MHz. Moreover, transmission zeros are generated near the passband, resulting in high selectivity for each tuning state. Comparisons between the measured and simulated results are presented and good agreement is observed.Index Terms-Bandpass response, constant absolute bandwidth, high selectivity, integration, tunable power divider.

Dual‐band filtering power divider with capacitor‐loaded centrally coupled‐line resonators

“…Since the impedance of port 1 becomes 100 I under the even7mode excitation, when extracting the coupling coefficients and external quality factors, the impedance of port 1 should be set as 100 I in simulation [8]. The extracting methods of coupling coefficients and external quality factors based on CLCCLRs in a 50 I system have been detailed in our previous work [21].…”

An Electronically Tunable Dual-Band Filtering Power Divider With Tuning Diodes Sharing Technique

“…Tunable filtering power dividers, integrating the two types of components, have attracted much attention in [7][8][9][10][11][12][13][14][15]. [7][8][9][10] present that filtering power dividers are tuned by varactors, each of them having one tunable passband.…”

“…[7][8][9][10] present that filtering power dividers are tuned by varactors, each of them having one tunable passband. Tunable filtering power dividers with constant absolutely bandwidth are reported in [7], and controllable bandwidth is reported in [8].…”

“…[7][8][9][10] present that filtering power dividers are tuned by varactors, each of them having one tunable passband. Tunable filtering power dividers with constant absolutely bandwidth are reported in [7], and controllable bandwidth is reported in [8]. However, the number of varactors to ports ratio, in [7][8][9][10], is no less than 1, which involves a more complex bias circuit and higher cost.…”

“…Tunable filtering power dividers with constant absolutely bandwidth are reported in [7], and controllable bandwidth is reported in [8]. However, the number of varactors to ports ratio, in [7][8][9][10], is no less than 1, which involves a more complex bias circuit and higher cost. A tunable filtering power divider, utilizing a piezoelectric linear actuator, is reported in [11], whereas the size of the actuator is very bulky.…”