A miniaturized microstrip‐to‐CPW transition based UWB‐BPF with sharp roll‐off and minimum insertion loss

Abstract

A novel ultrawideband (UWB) bandpass filter (BPF) based on broadside coupled microstrip‐to‐coplanar waveguide (CPW) transition is proposed. The proposed structure consists of open circuited microstrip lines on the top arranged in back‐to‐back fashion and electromagnetically coupled to a short circuited CPW in the ground via the dielectric. This arrangement generates a smooth UWB having passband insertion loss <0.22 dB in simulation, and two transmission zeros at the lower and upper passband/stopband edges which enhances selectivity. To validate the theory a prototype is fabricated and its measured response tested against simulated data. The simulation and measured response are found to be in good agreement with each other. The proposed structure is quite compact in size measuring only 14.8 × 9.6 mm2. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:289–293, 2016

A Compact Ultra-Wideband Bandpass Filter With Sharp Roll-Off Based on CPW-to-Microstrip Coupling Structure

“…In recent years, several methods and structures have been proposed to implement UWB bandpass filter (BPF) with compact size, sharp roll-off, low insertion loss and wide bandwidth [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Among the reported UWB BPFs, the interdigital coupled-line, which can create a UWB bandpass response and the multi-mode resonators (MMR) are the most widely used structures [2][3][4][5][6][7].…”

“…At the same time, several other UWB BPFs have been reported based on the hybrid structures. For example, CPW-to-microstrip transitions structures [8,10] and microstrip-to-CPW transition structures [11,12] have been used to design UWB BPFs. In these filters, their main structures are microstrip-CPW or CPW-microstrip transition.…”

Novel UWB BPF with a controllable notched band using hybrid structure

“…In the recent reported literatures, several methods and structures have been proposed to implement UWB BPF with compact size, sharp roll-off, low insertion loss and wide bandwidth [1,2,3,4,5,6,7,8,9,10,11]. For example, the MMR [1], defected microstrip structure [2] and some transition structures have been widely used to design UWB BPF [3,4,5]. At the same time, to block some undesired signals such as WLAN (5.2 GHz) and ITU8.0 (8.2 GHz) in the passband of the UWB, various structures and methods have been proposed to obtain a notched band [6,7,8,9,10,11].…”

A Compact Uwb BPF With Sharp Roll-Off Using CPW to Microstrip Transition Structure

“…As a result, several ideas and structures have been reported to implement UWB BPF [2][3][4][5][6][7][8][9][10][11][12][13]. In [2], a modified U-shaped MMR which has five resonance frequencies was used to improve the selectivity at upper edge of the passband.…”

“…In these filters, input signal flows through two different signal paths so as to produce extra transmission zeros at the passband edges. Some transition structures have also been used to design ultra-wideband bandpass filter such as CPW-to-microstrip (MS) transitions [6][7][8] and MS-to-CPW transitions [9,10]. In addition, some novel structures such as defected microstrip (DMS) structures [11,12] and defected ground structures (DGS) [13] have been proposed in the last few years.…”