Hybrid Microstrip Diplexer Design for Multi-band WiMAX Application in 2.3 and 3.5 GHz Bands

In this paper, a design of hybrid microstrip diplexer is proposed for multi-band Worldwide Interoperability for Microwave Access (WiMAX) application in 2.3 and 3.5 GHz bands. The diplexer consists of a combination of two different filter designs. These filters were designed based on microstripline coupling techniques in order to obtain minimum insertion losses and achieve the desired frequency bandwidth. Therefore, a coupled open loop ring resonator was chosen for the filter design in 2.3 GHz band and a folded coupled line resonator was chosen for the filter design in 3.5 GHz band. Then, these filters were combined with a ring manifold matching network to be a hybrid microstrip diplexer. Based on the results, good agreements were achieved between the simulation and measurement results in terms of insertion loss, return loss and bandwidth in the 2.3 and 3.5 GHz bands

Low Cost Tunable Bandstop Filter Design of Defected Ground Structure using FR4 Substrate

Abstract- This paper presents a tunable bandstop filter design using defected ground structure (DGS) where FR4 substrate is used as a low cost solution compared to others substrate such as Teflon and Rogers RT/Duroid. Thus, the performance of the tunable DGS bandstop filter using FR4 substrate is analyzed in this paper. Besides, analytical modeling of the tunable bandstop filter is derived and discussed as well where the tunable element of varactor diodes are used in the design. As result, tuning range in simulation is achieved from center frequency of 0.445 to 1.99GHz while the tuning range of fabricated filteris from 0.495 to 1.88GHz. The range of bandstop attenuation is between 9 to 46 dB for tuning voltage between 0 to 8 V

Analysis of switching and matching stubs in reconfigurable power divider with SPDT switch function

In this paper, performance analysis of switching and matching stubs was done to a reconfigurable power divider with Single Pole Double Throw (SPDT) switch function. Two designs (Design A and Design B) with different positions of switches and matching stubs were proposed. Rogers RO4350 (er=3.48, h=0.508 mm) was used in this analysis as a substrate material with copper thickness of 0.035 mm. The performance analysis was carried out based on insertion loss, return loss and isolation parameters. The simulated results showed that Design B had a better performance than Design A and was able to work as a reconfigurable power divider with SPDT switch function

A coupled-line balun for ultra-wideband single-balanced diode mixer

A multi-section coupled-line balun design for an ultra-wideband diode mixer is presented in this paper. The multi-section coupled-line balun was used to interface with the diode mixer in which it can deliver a good impedance matching between the diode mixer and input/output ports. The mixer design operates with a Local Oscillator (LO) power level of 10 dBm, Radio Frequency (RF) power level of -20 dBm and Intermediate Frequency (IF) of 100 MHz with the balun characteristic of 180° phase shift over UWB frequency (3.1 to 10.6 GHz), the mixer design demonstrated a good conversion loss of -8 to -16 dB over the frequency range from 3.1 to 10.6 GHz. Therefore, the proposed multi-section coupled-line balun for application of UWB mixer showed a good isolation between the mixer’s ports

Design of Reconfigurable Defected Ground Structure (DGS) for UWB Application

This paper presents the design of reconfigurable defected ground structure (DGS) resonator that can be integrated with ultrawide-band (UWB) microwave filter to produce bandpass and bandstop response simultaneously. The reconfigurable DGS is designed based upon coplanar waveguide (CPW) technology to exhibit bandstop characteristic at 3.5 GHz and 5.5 GHz using FR-4 on a 1.6 mm dielectric substrate thick with dielectric constant er = 4.6. The simulation performance shows promising results that could be further validated during the experimental works. This topology of reconfigurable DGS is useful for applications when the undesired signals need to be removed such as in wideband systems

High Selectivity Microstrip Bandpass Filter Integrate with Ring Resonator Bandstop Filter

An integrated high selectivity microstrip wideband bandpass filter with ring resonator bandstop filter is presented in this paper. The bandpass filter consists of of 6 th λ⁄4 short circuited stubs and two-sections of open circuited stub at one end of the element. The integration with bandstop filter is realized using ring resonator. The experimental result shows that the bandwidth of the wideband bandpass filter is between 2.9 GHz – 5.8 GHz. The bandstop filter produced high selectivity and attenuation at resonant frequency of 5.05 GHz and Q-factor of 252.2. This type of filter is suitable for applications such as the multi-service and multiband communication system in order to discriminate the undesired signals

Effect of a Discrete PIN Diode on Defected Ground Structure

Abstract—This paper investigates the effect of a discrete PIN diode on Defected Ground Structure (DGS) where the different resonant frequency between ON and OFF state of the PIN diode is observed. Analytical modeling is determined and analyzed based on equivalent circuit of PIN diode and DGS. Then, a circuit simulation is performed using simulation software with different value of inductance and capacitance of DGS during ON and OFF state of the PIN diode. As a result, the resonant frequency of the PIN diode on the DGS shifted to higher frequency during ON state and shifted to lower frequency during OFF state. Besides, a larger value of inductance with a smaller value of capacitance of DGS will produce a larger range of resonant frequency between ON and OFF state and vice versa

Analysis of Open Stub Resonator and its Application in Dual Isolation Band of SPDT Switch Design

In this paper, an analysis of open stub resonator is presented and its application in dual isolation band of Single Pole Double Throw (SPDT) switch is proposed. A mathematical model and the characteristic of the bandstop of the resonator were analyzed and discussed. The open stub resonator was implemented using the microstrip transmission line and able to switch between bandstop and allpass responses. Frequency bands of 2.3 and 3.5 GHz were chosen to demonstrate the dual isolation band in the switch design. The performance results of the SPDT switch showed that the isolation was greater than 30 dB, return loss was greater than 10 dB and insertion loss less than 2 dB at the center resonant frequency of 2.3 and 3.5 GHz. The potential application of the proposed dual isolation band of SPDT switch is for multi band RF front-end system such as WiMAX, LTE, WiFi and HyperLAN

Simulation Analysis on the Potential Application of Matched Bandstop to Bandpass Filter in Filter Integrated SPDT Switch Design

This paper presents the simulation analysis on the potential application of matched bandstop to bandpass filter in filter integrated switch (FIS) design. The FIS consists of matched band-stop to bandpass filter integrated with single-pole-double-throw (SPDT) switch. The proposed design was demonstrated for 2.45 GHz applications in wireless data communication systems such as Bluetooth and Zigbee. The filter was based on L-shape lossy resonator, which can provide an absorptive feature. PIN diodes were used as switching elements for the SPDT switch and to reconfigure between band-stop and bandpass responses. Therefore, the key advantages of the proposed design are high isolation and good return loss at both ON- and OFF-state ports. As a result, the simulation showed the followings: higher than 10 dB of return loss and greater than 25 dB of isolation at the operation frequency