диафрагмированные волноводные фильтры / 74401997-02d4-4392-9774-fc584e0ba0be

Abstract—Waveguide switchable bandstop and bandpass

filter designs are demonstrated in this paper. The designs are

based on the design of rectangular waveguide that has

switching

planar

bandstop

resonators

inserted

on the

Switching

MEMS model

ON-state

OFF-state

sidewall. These

switchable

bandstop

resonators

consist

of

Elements

Resonator

two identical metal patches separated by switching elements.

Length (L)

The

switching

elements

can

be

of

RF

MEMS

or

b

semiconductor transistor type. These resonators allow

electrically switching of the waveguide while providing close

(a)

Transistor model

ON-state

OFF-state

to ideal on-state insertion loss and narrow stop band during

off-state. These switches permit the switchable bandstop and

bandpass filters design. The concept is demonstrated for a

switchable five-pole bandstop filter and a switchable three-

pole bandpass filter, both at the centre frequency of 14.25

GHz and for 500 MHz bandwidth.

Switches off

Switches on

I. INTRODUCTION

(c)

Multi-band operation will become

a

standard

Fig.

1.

(a)

Switchable

planar

resonator located

inside

a

typical

in rectangular

waveguide,

(b)

the

designs

and

circuit models

when

using

adaptive

and

reconfigurable

RF

frontends.

Achieving

MEMS and transistors, and (c) the EM propagation when the switches

multi-standard

while

maintaining

low-cost

andare off and on.

compactness are becoming a trend in

communication

II. WAVEGUIDE SWITCH DESIGN

systems. Devices in the RF frontend, such as antennas,

switches, matching networks, phase shifters, directional

to

The design of our waveguide switch is based on a low

couplers

and

filters,

will

all

be

required

be

Q-factor switchable planar resonator. This resonator is

reconfigurable in the future. Some

antenna

designs designed

to

operate

within a

rectangular

waveguide,

in

showing promising results have been

reported

[1-5].

particular, attached

on

the

narrow sidewall,

as illustrated

However,

the most

critical

ones,

switches and

filters,

still

in

Fig.

1.

The concept

utilizes

the

planar

resonator

to

require significant research and development, especially in

create

a

bandstop

notch

at

a narrow band of frequencies

the

waveguide

technology.

If

conventional

waveguide

when

the switches

between the

two

patches are

enabled.

switches, typically rotary mechanical are well researched

When the switches are disabled, the band

stop

notch

is

and competing with the semiconductor PIN diodes, FET

switches

and

RF

MEMS

the

reconfigurable

waveguide

also disabled and therefore, the waveguide will permit

filter research is still limited [6]-19].

transmission.

The

switching

elements

can

be

of

RF

Reconfigurable filters reported in the literature

were

MEMS type or semiconductor transistor type. Due to the

most utilizing semiconductor PIN diodes and FET types,

planar nature, only low Q-factor value could be achieved

ferroelectric type, and RF MEMS type

switches

and

even when the resonator is operating inside a waveguide.

varactors. They offer the necessary reconfigurability and

They

are

easy

to

fabricate

and

can

be

switche

the required bandwidth; their achievable

Q-factors

are

electronically with minimal special modification to the

limited when compared with the waveguide counterparts.

waveguide.

One solution to achieve waveguide reconfigurable filters is

to combine waveguide switches with filters. To authors’

knowledge, partial research has been performed. Most

researchers only reported waveguide switches aiming to

improve either size and cost or the RF performance. One

group reported movable MEMS cantilevers with ridge

waveguide [20]. Another utilised a reconfigurable mesh

with MEMS actuator that covers the entire propagation

plane

[21].

In this paper, a concept

of

combining

waveguide switches together with filters

together

is

presented. The basic waveguide switch will be discussed,

followed by the bandstop and bandpass filter examples.

(a)

shows

the

circuit

model

of

one

switchable

resonator

Ratio and Reduced Sidelobe Level,"IEEE Antennas and Wireless

placed

within

a waveguide

cavity.

As

in

the

figure,

the

[2]

Propagation Letters, vol. 15, pp. 1835-1838, 2016.

cavity resonance is generated with a waveguide section of

Y. Yang, Y. Cai, K. Y. Chan, R. Ramer, and Y. J. Guo, "MEMS-

Loaded Millimeter Wave Frequency Reconfigurable Quasi-Yagi

λ/2 long bounded by two impedance inverters. When the

Dipole

Antenna," Microwave Conference Proceedings (APMC),

planar resonator is enabled, the switch in Fig. 6 is enabled

2011 Asia-Pacific, 2011, pp. 1318-1321: IEEE.

allowing

a

shorted

path

within

the

resonant

cavity

and

[3]

G. I. Kiani, T. S. Bird, and K. Y. Chan, "MEMS Enabled

effectively disabling the cavity resonance. Fig. 7(a) shows

Frequency Selective Surface for 60 GHz Applications,"Antennas

and Propagation (APSURSI), 2011 IEEE International

half of the simulated model of the switchable bandpass

Symposium on, 2011, pp. 2268-2269: IEEE.

filter (three-pole). Fig. 7(b)

illustrates

the

simulation

[4]

Y. Yang, K. Y. Chan, N. Nikolic, and R. Ramer, "Experimental

results

when

the

switches

are

on

and

off.

As

expected

Proof for Pattern Reconfigurability of 60GHz Quasi Yagi

from

the

circuit

model,

the

passband,

14

to

14.5

GHz

Antenna," Microwave and Optical Technology Letters, vol.

57,

no. 1, pp. 84-88, 2015.

either has a perfect transmission when the switches are

[5]

L.

Gong,

K. Chan, and R. Ramer, "A Split-Ring Structures

disabled (off) or has a high rejection

when

the switches

Loaded Siw Sectorial Horn Antenna,"Antennas and Propagation

are enabled

(on). However,

as

can

be

noticed,

when

the

in Wireless Communications (APWC), 2015 IEEE-APS Topical

switches

are

enabled,

the

out-of-band

performance

has

Conference on, 2015, pp. 349-350: IEEE.

[6]

F. Huang, S. Fouladi, and R. R. Mansour, "High-Q Tunable

significant changes and could be unacceptable for some

Dielectric Resonator Filters Using Mems Technology,"IEEE

applications.

Transactions on Microwave Theory and Techniques, vol. 59, no.

12, pp. 3401-3409, 2011.

λ/4

λ/4

[7] F. Huang and R. Mansour, "A Novel Varactor Tuned Dielectric

Resonator

Filter," IEEE

MTT-S

International

Microwave

Symposium Digest (IMS), Seattle, WA, USA, 2013, pp. 1-3.

Kij

Kij

[8]

H. Joshi, H. H. Sigmarsson, M. Sungwook, D. Peroulis, and W. J.

Chappell,

"High-Q Fully Reconfigurable Tunable

Bandpass

Filters," IEEE Transactions on Microwave Theory and

Fig. 6.

A proposed circuit model of a switchable planar resonator placed

Techniques, vol. 57, no. 12, pp. 3525-3533, 2009.

[9]

X. Liu, L. P. B. Katehi, W. J. Chappell, and D. Peroulis, "High-Q

within a rectangular waveguide resonator that is bounded by impedance

Tunable Microwave Cavity Resonators and

Filters

Using Soi-

inverters.

Based

Rf

Mems

Tuners,"Journal

of Microelectromechanical

Systems, vol. 19, no. 4, pp. 774-784, 2010.

[10]

F. Gentili, F. Cacciamani, V. Nocella, R. Sorrentino, and L.

rW

Pelliccia, "Rf Mems Hairpin Filter with Three Reconfigurable

WR62

rL

Bandwidth

States," European Microwave

Conference

(EuMC),

2013, pp. 802-805.

t

L1

t

L2

t

L1

t

[11]

F. Gentili, V. Nocella, L. Pelliccia, F. Cacciamani, P. Farinelli,

and R. Sorrentino, "Mems-Based Fine Tuning of High Q-Factor

E-Plane

Filters," International

Journal

of

Microwave

and

(a)

Wireless Technologies, vol. 6, no. 05, pp. 467-472, 2014.

[12] F. Gentili,

L. Pelliccia, R. Sorrentino, and G. Bianchi, "High Q-

Factor Compact Filters with Wide-Band Spurious Rejection,"

European Microwave Conference (EuMC), 2012, pp. 160-163.

[13] L. Pelliccia, P. Farinelli, R. Sorrentino, G. Cannone, G. Favre, and

P.

Coassini,

"K-Band

Mems-Based

Frequency

Adjustable

Waveguide

Filters for Mobile Back-Hauling,"International

Journal of Microwave and Wireless Technologies, vol. 8, no. 4-5,

pp. 751-757, 2016.

[14] H. Rahman, K. Y. Chan, Y. Yang, and R. Ramer, "Fabrication of

RF

NEMS

Series

Switch

Using

Surface

Micromachining,"

IASTED Intl. Conf. on Nanotechnology and Applications, 2010.

[15] Y. X. Yang,

K. Y. Chan, and R. Ramer,

"Wideband

RF Nano

Switch

Matrix," Antennas

and

Propagation (APSURSI), 2011

(b)

IEEE International Symposium on, 2011, pp. 1605-1608: IEEE.

[16]

E. Siew, K. Y. Chan, R. Ramer, and A. Dzurak, "Design of a RF

Fig. 7. (a) Half of the iris waveguide filter loaded with planar switchable

Nems

Switch

Matrix,"Antennas and Propagation (APSURSI),

resonators and (b) its simulation results showing the on and off states.

2011 IEEE International Symposium on, 2011, pp. 12-15: IEEE.

V.

CONCLUSIONS

[17]

X. Li, K. Y. Chan, and R. Ramer, "Fabrication of through Via

Holes in Ultra-Thin Fused Silica Wafers for Microwave and

This paper presented electrically-controlled waveguide

Millimeter-Wave Applications," Micromachines, vol. 9,

no. 3, p.

138, 2018.

switches, switchable bandpass and bandstop filter designs

[18]

L. Gong, K. Y. Chan, and R. Ramer, "A Third Order Bandpass

using

switchable

resonators.

A

five-pole

bandstop

filter

Iris Filter with Reconfigurable Dielectric Irises,"Microwave and

and a three-pole bandpass filter demonstrating their

Optical Technology Letters, vol. 60, no. 5, pp. 1287-1290, 2018.

[19]

L. Gong, K. Y. Chan, and R. Ramer, "A

Four-State

Iris

corresponding on and off states with their simulated RF

Waveguide Bandpass Filter with Switchable Irises,"Microwave

performance are shown. The design examples confirmed

Symposium (IMS), 2017 IEEE MTT-S International,

2017, pp.

the versatility of our approach, illustrated the potential of

260-263: IEEE.

such

designs

and

highlighted

the

simplicity

of

their

[20]

M. Daneshmand, R. R. Mansour, and N. Sarkar, "RF MEMS

fabrication.

Waveguide

Switch," IEEE Transactions on Microwave Theory

and Techniques, vol. 52, no. 12, pp. 2651-2657, 2004.

REFERENCES

[21]

Z. Baghchehsaraei and J. Oberhammer, "Parameter Analysis of

Millimeter-Wave Waveguide Switch Based on a MEMS-

[1]

L.

Gong,

K.

Y.

Chan,

and

R.

Ramer,

"Substrate

Integrated

Reconfigurable

Surface," IEEE

Transactions

on

Microwave

Theory and Techniques, vol. 61, no. 12, pp. 4396-4406, 2013.

Waveguide H-Plane Horn Antenna with Improved Front-to-Back