Hybrid Microstrip Compact Bandpass Filter Using High Permittivity Substrate

Abstract

Abstract-A four-pole elliptic function compact bandpass filter is designed by using interdigital hairpin resonator and step-impedance hairpin resonator.The miniaturized band-pass filter is also implemented using high permittivity dielectric substrate. The fullwave simulator IE3D is used to design the compact hairpin resonator, and to calculate the coupling coefficient of the basic coupling strictures. The responses of the fabricated filters using Al 2 O 3 (ε r = 9.7, Q × f = 350000 GHz) and 0.6Sm(Co 1/2 Ti 1/2 )O 3 -0.4CaTiO 3 (ε r = 37, Q × f = 43000 GHz) dielectric substrates are designed at a center frequency of 2 GHz. The size of the compact hairpin filter using 0.6Sm(Co 1/2 Ti 1/2 )O 3 -0.4CaTiO 3 ceramic substrate, as compared to that of a compact hairpin filter using Al 2 O 3 ceramic substrate, is reduced in size by 45%. The compact size and good agreement have been obtained between simulations and implementation results.

A Miniaturized Bandpass Filter With Controllable Harmonic by Using Split Impedance Resonators

“…Furthermore, as shown in Equation 6, the impedance Z 2 was presented as Z 1 /N , when impedance Z 2 was divided as numerous impedance Z 1 . Letting θ 2 = θ 1 , in this case, the Equation 7is given from Equation (4), and the controllable spurious frequency f S1 is verified as Equation (8). In this paper, Equations (6) and (8) were Figure 2.…”

“…3 shows the relationship of spurious resonant frequency f S1 and frequency ratio f S1 /f 0 versus the numbers of split impedance section (N ). Then, the proposed split impedance bandpass filter was realized based on Equations (6), (8), and Fig. 3.…”

“…In this paragraph, based on the theories of the basic parallel impedance formula, the lower-impedance sections of traditional stepped impedance resonator were transferred to numerous higher impedance sections by using the proposed Equations (6), (8), and Fig. 3.…”

“…Hong also proposed that stepped impedance resonator bandpass filter can achieve the harmonic suppression to improve the stability of the system [3,4]. In recent years, the stepped impedance resonator has been frequently applied to control the harmonic to be the second passband [5,6] or improve the out-of-band performance [7][8][9][10]. However, the coupling between two different impedances has been a common problem for traditional stepped impedance resonators.…”

Circularly polarized slotted‐ground microstrip antennas for radiofrequency identification readers

“…A typical technique for producing the CP radiation from the single‐feed microstrip antenna is to excite two orthogonal linearly polarized modes with a 90° difference [2]. Various methods have been applied to reduce the size of the CPMAs such as slots cut on a radiating patch [1–4], the antenna design on a high dielectric substrate [5], the antenna design with shorting pins [6], patch with ring/stub [7, 8], slit cuts on a radiating patch [9–11], and artificial magneto‐dielectric substrate [12]. The CPMAs on the slotted‐ground plane have been proposed for size reduction [13, 14].…”