Modern communication systems often use dual band bandpass filters to isolate different operating bands in the same network. The traditional design dimensions of such filters are relatively large and require an additional combined network for the two filters. However, the dual-band bandpass filter design method discussed in detail in this paper can be made very small. Its structure is relatively simple, consisting of two asymmetric split spiral resonators (ASSR) cascaded with a microstrip line. Due to the inherent spiral geometry of the ASSR, the ASSR can be fully embedded in the microstrip line, so the final design size can be minimized. This paper also further analyzes this innovative design and validates this design approach with a pair of prototypes. The two dual band filters operate between 1.16 GHz and 1.84 GHz and between 1.80 GHz and 2.45 GHz, respectively. The industry has made a lot of efforts to miniaturize the dual-band bandpass filter. For example, a cross-coupled filter is a relatively efficient solution. In this design method, an isometric split-ring resonator with dual resonant frequency response characteristics is used as the basis for the design of the filter. In one example, a cross-coupled dual-band bandpass filter is synthesized using four resonators, and the relative positions of these resonators must be carefully tuned in order to obtain a suitable coupling coefficient. Unfortunately, the use of four resonators results in reduced insertion loss performance and the difficulty of achieving compact dimensions (especially cross-sectional dimensions). Another approach is to use an open-loop resonator and a parallel open stub as the basis for the design of a compact dual-band bandpass filter. Designed and manufactured here are three dual-band filters optimized for out-of-band rejection. In these prototypes, the second passband can be controlled by adjusting the position and length of a particular parallel open stub. There is also a micro-planar dual-band bandpass filter based on a curved stepped impedance resonator (SIR). The dual-band response of this filter depends on the main geometric parameters of the SIR, while the compact size is achieved by integrating the U-shaped SIR with the latest coupling mechanism. A miniature dual-band bandpass filter is also implemented using a combined coupling structure of short and open quarter-wavelength SIR. In summary, these different dual-band filter design methods rely on a basic unit with a dual resonant mode. This article provides different design methods for creating compact, dual-band bandpass filters. In this new approach, the filter consists of two cascaded ASSRs connected by microstrip lines. These ASSRs are an improved version of a single plane double helix resonator unit and a symmetric split type spiral resonator. Due to its special geometry, this ASSR can be fully embedded in the microstrip feed line to directly form the corresponding component with a compact cross-sectional dimension. In general, ASSR is a band-pass unit that operates by electromagnetic (EM) coupling. In the current design, the first passband is dependent on the inherent passband of the ASSR, while the second passband is created by a combination of an equal impedance network of ASSRs and connected microstrip lines. Thus, the second passband can be adjusted independently of the first passband by using the length of the connected microstrip line as a variable parameter. This conclusion will also be verified by circuit model analysis. Based on this analysis, we designed and fabricated two different dual-band bandpass filters to demonstrate the effectiveness of the analysis. According to our knowledge, these dual-band bandpass filters are the narrowest filters reported in all the literature to date due to their particularly compact cross-sectional dimensions. Figure 1: The layout shows ASSR(a) and the recommended dual-band bandpass filter (b). This filter uses a pair of ASSRs and a microstrip transmission line connected to it. Figure 1 shows the ASSR layout (a) and recommended filter (b) used in this dual-band bandpass filter. Each ASSR consists of two separate, asymmetrical rectangular spiral patterns. Due to the rotational geometry of the rectangular helix, a given unit can be fully embedded within the microstrip line, resulting in a particularly compact cross-sectional dimension. Thus, the ASSR Broadband W1 remains unchanged at 4.6 mm, which is equivalent to the width of a 50Ω microstrip line fabricated on Rogers' RT/duroid 5880 printed circuit board (PCB) substrate. The relative dielectric constant of this substrate is 2.2. The thickness is 1.5mm. These material values ​​are also used for simulation. The values ​​for dimensions W3 and W4 are limited due to limitations imposed by circuit manufacturing tolerances (approximately 0.1 mm at W1 = 4.6 mm). For these dual band bandpass filter designs, the values ​​for W3 = 0.6 mm and W4 = 0.3 mm are used here. In a common model of a coupled microstrip line filter, these values ​​will support the effective bandpass properties through electromagnetic coupling. This prediction will be verified by the parameter analysis method of L1 (the main adjustment parameter of the bandpass filter), and the result is shown in Fig. 2. Parabolic Reflex Reflector,Parabolic Grow Reflector,Aluminum Lamp Reflector,Safety Lighting Covers Yangzhou Huadong Can Illuminations Mould Manufactory Co., Ltd. , https://www.light-reflectors.com