New Designs of Bandpass Diplexer and Switchplexer Based on Parallel-Coupled Bandpass Filters

Abstract

In this paper, new designs of a bandpass diplexer and switchplexer are presented. Based on the proposed design method, they can be implemented by the direct connection of two parallelcoupled bandpass filters. As a result, the circuit size and mismatch losses can be reduced compared with conventional designs. In addition, based on the proposed filter prototypes, multiple functional blocks in the RF front end can be integrated into a single component. As an example, a balun-integrated bandpass switchplexer that effectively integrates all the functional blocks between the antenna and the TX/RX amplifiers in a single-band RF transceiver is demonstrated. In this way, not only can the level of integration of the RF front end be further improved, but the circuit size and power losses can also be reduced.

Design of a Switchplexer Based on a Microstrip Ring Resonator with Single-Switch Operation

“…The technique for multi-band and multi-functional capabilities using the diode and switch has also been found to be useful in other microwave applications, such as for use with reconfigurable antennas [8,9]. Recently, the diplexer and switch in time-division communications systems were combined into one device, called the switchplexer [10][11][12]. Fig.…”

“…1 shows the concept of the switchplexer [12], which integrates both the switch and the diplexer. The switch can change the signal path between the receiving and transmitting signals, as described in [11,12], or it can change the signal path between the two receiving signals with different bands, as shown in [10]. The diplexer consists of two or more bandpass filters.…”

“…The diplexer consists of two or more bandpass filters. The benefit of the switchplexer is that it decreases the insertion loss and the amount of space occupying, making even the design process easier [10]. This paper proposes a new microstrip switchplexer that can change the current distribution electrically on the rectangular ring resonator using only single-switch operation.…”

“…Meanwhile, the switchplexer studied in [12] integrates the switch, diplexer, and low-noise amplifier (LNA). The switch integrated in [10] is the double-pole double-throw (DPDT) switch, and it is connected to two antennas for multiple-input multipleoutput (MIMO). The proposed switchplexer in this paper contains the switch and diplexer consisting of two band-pass filters.…”

“…This accomplished a simple and low-cost switchplexer. The diplexer of previous work described in [8][9][10][11] was configured with the cascaded filters. However, the diplexer of the proposed switchplexer is the simple one resonator.…”